Index: /trunk/src/VBox/Frontends/VirtualBox/src/globals/UIMessageCenter.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/globals/UIMessageCenter.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/globals/UIMessageCenter.cpp	(revision 66626)
@@ -1071,81 +1071,4 @@
 }
 
-void UIMessageCenter::cannotSaveDisplaySettings(const CSystemProperties &comProperties, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save display settings."),
-          formatErrorInfo(comProperties));
-}
-
-void UIMessageCenter::cannotSaveGeneralSettings(const CSystemProperties &comProperties, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save general settings."),
-          formatErrorInfo(comProperties));
-}
-
-void UIMessageCenter::cannotSaveInputSettings(const CSystemProperties &comProperties, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save input settings."),
-          formatErrorInfo(comProperties));
-}
-
-void UIMessageCenter::cannotSaveLanguageSettings(const CSystemProperties &comProperties, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save language settings."),
-          formatErrorInfo(comProperties));
-}
-
-void UIMessageCenter::cannotLoadNetworkSettings(const CVirtualBox &comVBox, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot load network settings."),
-          formatErrorInfo(comVBox));
-}
-
-void UIMessageCenter::cannotLoadNetworkSettings(const CHost &comHost, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot load network settings."),
-          formatErrorInfo(comHost));
-}
-
-void UIMessageCenter::cannotSaveNetworkNatSettings(const CNATNetwork &comNetwork, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save NAT network settings."),
-          formatErrorInfo(comNetwork));
-}
-
-void UIMessageCenter::cannotSaveNetworkHostSettings(const CHostNetworkInterface &comInterface, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save host-only network settings."),
-          formatErrorInfo(comInterface));
-}
-
-void UIMessageCenter::cannotSaveDHCPServerSettings(const CDHCPServer &comServer, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save DHCP server settings."),
-          formatErrorInfo(comServer));
-}
-
-void UIMessageCenter::cannotSaveProxySettings(const CSystemProperties &comProperties, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save proxy settings."),
-          formatErrorInfo(comProperties));
-}
-
-void UIMessageCenter::cannotSaveUpdateSettings(const CSystemProperties &comProperties, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save update settings."),
-          formatErrorInfo(comProperties));
-}
-
 void UIMessageCenter::warnAboutUnaccessibleUSB(const COMBaseWithEI &object, QWidget *pParent /* = 0*/) const
 {
@@ -1229,200 +1152,4 @@
                           QString() /* cancel button text */,
                           false /* ok button by default? */);
-}
-
-void UIMessageCenter::cannotSaveAudioSettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save audio settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotSaveAudioAdapterSettings(const CAudioAdapter &comAdapter, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save audio adapter settings."),
-          formatErrorInfo(comAdapter));
-}
-
-void UIMessageCenter::cannotSaveDisplaySettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save display settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotSaveRemoteDisplayServerSettings(const CVRDEServer &comServer, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save remote display server settings."),
-          formatErrorInfo(comServer));
-}
-
-void UIMessageCenter::cannotSaveGeneralSettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save general settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotSaveStorageAttachmentSettings(const CMediumAttachment &comAttachment, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save storage attachment settings."),
-          formatErrorInfo(comAttachment));
-}
-
-void UIMessageCenter::cannotSaveStorageMediumSettings(const CMedium &comMedium, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save storage medium settings."),
-          formatErrorInfo(comMedium));
-}
-
-void UIMessageCenter::cannotSaveInterfaceSettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save user interface settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotSaveNetworkSettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save network settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotSaveNetworkAdapterSettings(const CNetworkAdapter &comAdapter, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save network adapter settings."),
-          formatErrorInfo(comAdapter));
-}
-
-void UIMessageCenter::cannotSaveNATEngineSettings(const CNATEngine &comEngine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save NAT engine settings."),
-          formatErrorInfo(comEngine));
-}
-
-void UIMessageCenter::cannotSaveParallelSettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save parallel ports settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotSaveParallelPortSettings(const CParallelPort &comPort, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save parallel port settings."),
-          formatErrorInfo(comPort));
-}
-
-void UIMessageCenter::cannotSaveSerialSettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save serial ports settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotSaveSerialPortSettings(const CSerialPort &comPort, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save serial port settings."),
-          formatErrorInfo(comPort));
-}
-
-void UIMessageCenter::cannotLoadFoldersSettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot load shared folders settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotSaveFoldersSettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save shared folders settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotLoadFoldersSettings(const CConsole &comConsole, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot load shared folders settings."),
-          formatErrorInfo(comConsole));
-}
-
-void UIMessageCenter::cannotSaveFoldersSettings(const CConsole &comConsole, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save shared folders settings."),
-          formatErrorInfo(comConsole));
-}
-
-void UIMessageCenter::cannotLoadFolderSettings(const CSharedFolder &comFolder, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot load shared folder settings."),
-          formatErrorInfo(comFolder));
-}
-
-void UIMessageCenter::cannotSaveFolderSettings(const CSharedFolder &comFolder, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save shared folder settings."),
-          formatErrorInfo(comFolder));
-}
-
-void UIMessageCenter::cannotSaveStorageSettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save storage settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotSaveStorageControllerSettings(const CStorageController &comController, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save storage controller settings."),
-          formatErrorInfo(comController));
-}
-
-void UIMessageCenter::cannotSaveSystemSettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save system settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotSaveUSBSettings(const CMachine &comMachine, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save USB settings."),
-          formatErrorInfo(comMachine));
-}
-
-void UIMessageCenter::cannotSaveUSBControllerSettings(const CUSBController &comController, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save USB controller settings."),
-          formatErrorInfo(comController));
-}
-
-void UIMessageCenter::cannotSaveUSBDeviceFiltersSettings(const CUSBDeviceFilters &comFilters, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save USB device filters settings."),
-          formatErrorInfo(comFilters));
-}
-
-void UIMessageCenter::cannotSaveUSBDeviceFilterSettings(const CUSBDeviceFilter &comFilter, QWidget *pParent /* = 0 */)
-{
-    error(pParent, MessageType_Error,
-          tr("Cannot save USB device filter settings."),
-          formatErrorInfo(comFilter));
 }
 
Index: /trunk/src/VBox/Frontends/VirtualBox/src/globals/UIMessageCenter.h
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/globals/UIMessageCenter.h	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/globals/UIMessageCenter.h	(revision 66626)
@@ -229,15 +229,4 @@
     void cannotRemoveHostInterface(const CProgress &progress, const QString &strInterfaceName, QWidget *pParent = 0);
     void cannotSetSystemProperties(const CSystemProperties &properties, QWidget *pParent = 0) const;
-    void cannotSaveDisplaySettings(const CSystemProperties &comProperties, QWidget *pParent = 0);
-    void cannotSaveGeneralSettings(const CSystemProperties &comProperties, QWidget *pParent = 0);
-    void cannotSaveInputSettings(const CSystemProperties &comProperties, QWidget *pParent = 0);
-    void cannotSaveLanguageSettings(const CSystemProperties &comProperties, QWidget *pParent = 0);
-    void cannotLoadNetworkSettings(const CVirtualBox &comVBox, QWidget *pParent = 0);
-    void cannotLoadNetworkSettings(const CHost &comHost, QWidget *pParent = 0);
-    void cannotSaveNetworkNatSettings(const CNATNetwork &comNetwork, QWidget *pParent = 0);
-    void cannotSaveNetworkHostSettings(const CHostNetworkInterface &comInterface, QWidget *pParent = 0);
-    void cannotSaveDHCPServerSettings(const CDHCPServer &comServer, QWidget *pParent = 0);
-    void cannotSaveProxySettings(const CSystemProperties &comProperties, QWidget *pParent = 0);
-    void cannotSaveUpdateSettings(const CSystemProperties &comProperties, QWidget *pParent = 0);
 
     /* API: Machine settings warnings: */
@@ -249,32 +238,4 @@
     int confirmFloppyAttachmentCreation(const QString &strControllerName, QWidget *pParent = 0) const;
     int confirmRemovingOfLastDVDDevice(QWidget *pParent = 0) const;
-    void cannotSaveAudioSettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotSaveAudioAdapterSettings(const CAudioAdapter &comAdapter, QWidget *pParent = 0);
-    void cannotSaveDisplaySettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotSaveRemoteDisplayServerSettings(const CVRDEServer &comServer, QWidget *pParent = 0);
-    void cannotSaveGeneralSettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotSaveStorageAttachmentSettings(const CMediumAttachment &comAttachment, QWidget *pParent = 0);
-    void cannotSaveStorageMediumSettings(const CMedium &comMedium, QWidget *pParent = 0);
-    void cannotSaveInterfaceSettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotSaveNetworkSettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotSaveNetworkAdapterSettings(const CNetworkAdapter &comAdapter, QWidget *pParent = 0);
-    void cannotSaveNATEngineSettings(const CNATEngine &comEngine, QWidget *pParent = 0);
-    void cannotSaveParallelSettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotSaveParallelPortSettings(const CParallelPort &comPort, QWidget *pParent = 0);
-    void cannotSaveSerialSettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotSaveSerialPortSettings(const CSerialPort &comPort, QWidget *pParent = 0);
-    void cannotLoadFoldersSettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotSaveFoldersSettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotLoadFoldersSettings(const CConsole &comConsole, QWidget *pParent = 0);
-    void cannotSaveFoldersSettings(const CConsole &comConsole, QWidget *pParent = 0);
-    void cannotLoadFolderSettings(const CSharedFolder &comFolder, QWidget *pParent = 0);
-    void cannotSaveFolderSettings(const CSharedFolder &comFolder, QWidget *pParent = 0);
-    void cannotSaveStorageSettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotSaveStorageControllerSettings(const CStorageController &comController, QWidget *pParent = 0);
-    void cannotSaveSystemSettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotSaveUSBSettings(const CMachine &comMachine, QWidget *pParent = 0);
-    void cannotSaveUSBControllerSettings(const CUSBController &comController, QWidget *pParent = 0);
-    void cannotSaveUSBDeviceFiltersSettings(const CUSBDeviceFilters &comFilters, QWidget *pParent = 0);
-    void cannotSaveUSBDeviceFilterSettings(const CUSBDeviceFilter &comFilter, QWidget *pParent = 0);
     void cannotAttachDevice(const CMachine &machine, UIMediumType type, const QString &strLocation, const StorageSlot &storageSlot, QWidget *pParent = 0);
     bool warnAboutIncorrectPort(QWidget *pParent = 0) const;
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/UISettingsPage.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/UISettingsPage.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/UISettingsPage.cpp	(revision 66626)
@@ -39,4 +39,12 @@
     , m_fIsValidatorBlocked(true)
 {
+}
+
+void UISettingsPage::notifyOperationProgressError(const QString &strErrorInfo)
+{
+    QMetaObject::invokeMethod(this,
+                              "sigOperationProgressError",
+                              Qt::BlockingQueuedConnection,
+                              Q_ARG(QString, strErrorInfo));
 }
 
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/UISettingsPage.h
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/UISettingsPage.h	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/UISettingsPage.h	(revision 66626)
@@ -107,4 +107,8 @@
     virtual void saveFromCacheTo(QVariant &data) = 0;
 
+    /** Notifies listeners about particular COM error.
+      * @param  strErrorInfo  Brings the details of the error happened. */
+    void notifyOperationProgressError(const QString &strErrorInfo);
+
     /* Validation stuff: */
     void setValidator(UIPageValidator *pValidator);
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsDisplay.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsDisplay.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsDisplay.cpp	(revision 66626)
@@ -250,10 +250,4 @@
         const UIDataSettingsGlobalDisplay &newDisplayData = m_pCache->data();
 
-        // Here could go changes for m_properties.
-
-        /* Show error message if necessary: */
-        if (!fSuccess)
-            msgCenter().cannotSaveDisplaySettings(m_properties, this);
-
         /* Save maximum guest resolution policy and/or value: */
         if (   fSuccess
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsGeneral.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsGeneral.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsGeneral.cpp	(revision 66626)
@@ -211,5 +211,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveGeneralSettings(m_properties, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_properties));
 
         /* Save new general data from the cache: */
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsInput.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsInput.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsInput.cpp	(revision 66626)
@@ -1159,10 +1159,4 @@
         const UIDataSettingsGlobalInput &newInputData = m_pCache->data();
 
-        // Here could go changes for m_properties.
-
-        /* Show error message if necessary: */
-        if (!fSuccess)
-            msgCenter().cannotSaveInputSettings(m_properties, this);
-
         /* Save new host-combo shortcut from the cache: */
         const UIDataShortcutRow fakeHostComboItem(0, UIHostCombo::hostComboCacheKey(), QString(), QString(), QString());
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsLanguage.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsLanguage.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsLanguage.cpp	(revision 66626)
@@ -457,10 +457,4 @@
         const UIDataSettingsGlobalLanguage &newLanguageData = m_pCache->data();
 
-        // Here could go changes for m_properties.
-
-        /* Show error message if necessary: */
-        if (!fSuccess)
-            msgCenter().cannotSaveLanguageSettings(m_properties, this);
-
         /* Save new language data from the cache: */
         if (newLanguageData.m_strLanguageId != oldLanguageData.m_strLanguageId)
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsNetwork.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsNetwork.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsNetwork.cpp	(revision 66626)
@@ -1121,5 +1121,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotLoadNetworkSettings(comVBox, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comVBox));
         else
         {
@@ -1238,5 +1238,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveNetworkNatSettings(comNetwork, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comNetwork));
         }
     }
@@ -1333,5 +1333,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotLoadNetworkSettings(comHost, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comHost));
         else
         {
@@ -1381,5 +1381,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveNetworkHostSettings(comInterface, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comInterface));
             else
             {
@@ -1392,5 +1392,5 @@
                 /* Show error message if necessary: */
                 if (!fSuccess)
-                    msgCenter().cannotLoadNetworkSettings(comVBox, this);
+                    notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comVBox));
                 else
                 {
@@ -1415,7 +1415,5 @@
                     /* Show error message if necessary: */
                     if (!fSuccess)
-                        msgCenter().cannotSaveDHCPServerSettings(comServer, this);
-                    // if (!comServer.isOk())
-                    //    emit sigOperationProgressError(UIMessageCenter::formatErrorInfo(comServer));
+                        notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comServer));
                 }
             }
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsProxy.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsProxy.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsProxy.cpp	(revision 66626)
@@ -264,10 +264,4 @@
         const UIDataSettingsGlobalProxy &newProxyData = m_pCache->data();
 
-        // Here could go changes for m_properties.
-
-        /* Show error message if necessary: */
-        if (!fSuccess)
-            msgCenter().cannotSaveProxySettings(m_properties, this);
-
         /* Save new proxy data from the cache: */
         UIProxyManager proxyManager;
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsUpdate.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsUpdate.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/global/UIGlobalSettingsUpdate.cpp	(revision 66626)
@@ -259,10 +259,4 @@
         const UIDataSettingsGlobalUpdate &newUpdateData = m_pCache->data();
 
-        // Here could go changes for m_properties.
-
-        /* Show error message if necessary: */
-        if (!fSuccess)
-            msgCenter().cannotSaveUpdateSettings(m_properties, this);
-
         /* Save new update data from the cache: */
         const VBoxUpdateData newData(newUpdateData.m_periodIndex, newUpdateData.m_branchIndex);
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsAudio.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsAudio.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsAudio.cpp	(revision 66626)
@@ -273,5 +273,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveAudioSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
         else
         {
@@ -297,5 +297,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveAudioAdapterSettings(comAdapter, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comAdapter));
         }
     }
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsDisplay.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsDisplay.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsDisplay.cpp	(revision 66626)
@@ -1275,5 +1275,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveDisplaySettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
 
         /* Save guest-screen scale-factor: */
@@ -1308,5 +1308,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveDisplaySettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
         else
         {
@@ -1346,5 +1346,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveRemoteDisplayServerSettings(comServer, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comServer));
         }
     }
@@ -1485,5 +1485,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveDisplaySettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
     }
     /* Return result: */
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsGeneral.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsGeneral.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsGeneral.cpp	(revision 66626)
@@ -717,5 +717,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveGeneralSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
     }
     /* Return result: */
@@ -764,5 +764,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveGeneralSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
     }
     /* Return result: */
@@ -791,5 +791,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveGeneralSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
     }
     /* Return result: */
@@ -834,5 +834,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveGeneralSettings(m_machine, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
 
             /* For each attachment: */
@@ -859,5 +859,5 @@
                 /* Show error message if necessary: */
                 if (!fSuccess)
-                    msgCenter().cannotSaveStorageAttachmentSettings(comAttachment, this);
+                    notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comAttachment));
                 else
                 {
@@ -913,19 +913,8 @@
                     }
 
-                    // TODO: Decide what to do with it (also below).
-                    // if (!comMedium.isOk())
-                    // {
-                    //     QMetaObject::invokeMethod(this, "sigOperationProgressError", Qt::BlockingQueuedConnection,
-                    //                               Q_ARG(QString, UIMessageCenter::formatErrorInfo(comMedium)));
-                    //     continue;
-                    // }
-
                     /* Create encryption update progress dialog: */
                     QPointer<UIProgress> pDlg;
                     if (fSuccess)
                     {
-                        // TODO: Decide what to do with it (also above).
-                        // This dialog connected to settings serializer, not to message-center directly.
-                        // What's the better approach in that case? Probably connect everything to serializer?
                         pDlg = new UIProgress(comProgress);
                         connect(pDlg, SIGNAL(sigProgressChange(ulong, QString, ulong, ulong)),
@@ -948,5 +937,5 @@
                     /* Show error message if necessary: */
                     if (!fSuccess)
-                        msgCenter().cannotSaveStorageMediumSettings(comMedium, this);
+                        notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comMedium));
                 }
             }
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsNetwork.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsNetwork.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsNetwork.cpp	(revision 66626)
@@ -1499,5 +1499,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveNetworkSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
         else
         {
@@ -1601,5 +1601,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveNetworkAdapterSettings(comAdapter, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comAdapter));
             else
             {
@@ -1638,5 +1638,5 @@
                     /* Show error message if necessary: */
                     if (!fSuccess)
-                        msgCenter().cannotSaveNATEngineSettings(comEngine, this);
+                        notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comEngine));
                 }
             }
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsParallel.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsParallel.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsParallel.cpp	(revision 66626)
@@ -573,5 +573,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveParallelSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
         else
         {
@@ -603,5 +603,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveParallelPortSettings(comPort, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comPort));
         }
     }
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsSF.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsSF.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsSF.cpp	(revision 66626)
@@ -869,5 +869,5 @@
                 /* Show error message if necessary: */
                 if (!fSuccess)
-                    msgCenter().cannotLoadFoldersSettings(m_machine, this);
+                    notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
 
                 break;
@@ -883,5 +883,5 @@
                 /* Show error message if necessary: */
                 if (!fSuccess)
-                    msgCenter().cannotLoadFoldersSettings(m_console, this);
+                    notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_console));
 
                 break;
@@ -915,5 +915,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotLoadFolderSettings(comCurrentFolder, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comCurrentFolder));
 
         /* If that's the folder we are looking for => take it: */
@@ -988,5 +988,5 @@
                     {
                         /* Show error message: */
-                        msgCenter().cannotSaveFoldersSettings(m_machine, this);
+                        notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
                     }
                     break;
@@ -1001,5 +1001,5 @@
                     {
                         /* Show error message: */
-                        msgCenter().cannotSaveFoldersSettings(m_console, this);
+                        notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_console));
                     }
                     break;
@@ -1054,5 +1054,5 @@
                     {
                         /* Show error message: */
-                        msgCenter().cannotSaveFoldersSettings(m_machine, this);
+                        notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
                     }
                     break;
@@ -1067,5 +1067,5 @@
                     {
                         /* Show error message: */
-                        msgCenter().cannotSaveFoldersSettings(m_console, this);
+                        notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_console));
                     }
                     break;
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsSerial.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsSerial.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsSerial.cpp	(revision 66626)
@@ -630,5 +630,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveSerialSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
         else
         {
@@ -688,5 +688,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveSerialPortSettings(comPort, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comPort));
         }
     }
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsStorage.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsStorage.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsStorage.cpp	(revision 66626)
@@ -4026,5 +4026,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveStorageSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
     }
     /* Return result: */
@@ -4058,5 +4058,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveStorageSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
         else
         {
@@ -4099,5 +4099,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveStorageControllerSettings(comController, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comController));
 
             /* For each attachment: */
@@ -4135,5 +4135,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveStorageSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
         else
         {
@@ -4177,5 +4177,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveStorageControllerSettings(comController, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comController));
 
             /* For each attachment ('removing' step): */
@@ -4245,5 +4245,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveStorageSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
     }
     /* Return result: */
@@ -4335,5 +4335,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveStorageSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
     }
     /* Return result: */
@@ -4423,5 +4423,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveStorageSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
     }
     /* Return result: */
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsSystem.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsSystem.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsSystem.cpp	(revision 66626)
@@ -1139,5 +1139,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveSystemSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
     }
     /* Return result: */
@@ -1178,5 +1178,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveSystemSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
     }
     /* Return result: */
@@ -1217,5 +1217,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveSystemSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
     }
     /* Return result: */
Index: /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsUSB.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsUSB.cpp	(revision 66625)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/settings/machine/UIMachineSettingsUSB.cpp	(revision 66626)
@@ -1015,5 +1015,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveUSBSettings(m_machine, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
             else
             {
@@ -1060,5 +1060,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveUSBSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
 
         /* For each controller: */
@@ -1085,5 +1085,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveUSBControllerSettings(comController, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comController));
             else
             {
@@ -1101,5 +1101,5 @@
                 /* Show error message if necessary: */
                 if (!fSuccess)
-                    msgCenter().cannotSaveUSBSettings(m_machine, this);
+                    notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
             }
         }
@@ -1138,5 +1138,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveUSBSettings(m_machine, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
         else
         {
@@ -1160,5 +1160,5 @@
                         /* Show error message if necessary: */
                         if (!fSuccess)
-                            msgCenter().cannotSaveUSBSettings(m_machine, this);
+                            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
                     }
 
@@ -1188,5 +1188,5 @@
                         /* Show error message if necessary: */
                         if (!fSuccess)
-                            msgCenter().cannotSaveUSBSettings(m_machine, this);
+                            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
                     }
 
@@ -1209,5 +1209,5 @@
                         /* Show error message if necessary: */
                         if (!fSuccess)
-                            msgCenter().cannotSaveUSBSettings(m_machine, this);
+                            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(m_machine));
                     }
 
@@ -1236,5 +1236,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveUSBDeviceFiltersSettings(comFiltersObject, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comFiltersObject));
     }
     /* Return result: */
@@ -1255,5 +1255,5 @@
         /* Show error message if necessary: */
         if (!fSuccess)
-            msgCenter().cannotSaveUSBDeviceFiltersSettings(comFiltersObject, this);
+            notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comFiltersObject));
         else
         {
@@ -1315,5 +1315,5 @@
             /* Show error message if necessary: */
             if (!fSuccess)
-                msgCenter().cannotSaveUSBDeviceFilterSettings(comFilter, this);
+                notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comFilter));
             else
             {
@@ -1324,5 +1324,5 @@
                 /* Show error message if necessary: */
                 if (!fSuccess)
-                    msgCenter().cannotSaveUSBDeviceFiltersSettings(comFiltersObject, this);
+                    notifyOperationProgressError(UIMessageCenter::formatErrorInfo(comFiltersObject));
             }
         }
