Index: /trunk/include/VBox/com/Guid.h
===================================================================
--- /trunk/include/VBox/com/Guid.h	(revision 44090)
+++ /trunk/include/VBox/com/Guid.h	(revision 44091)
@@ -420,6 +420,6 @@
     {
 #ifdef DEBUG
-        ::RTUuidToStr(&mUuid, mszUuid, RTUUID_STR_LENGTH);
-        m_pcszUUID = mszUuid;
+//        ::RTUuidToStr(&mUuid, mszUuid, RTUUID_STR_LENGTH);
+//        m_pcszUUID = mszUuid;
 #endif
     }
@@ -444,10 +444,10 @@
 }
 */
-inline bool isValidGuid(const Bstr& str)
-{
-   Guid guid(str);
-   return guid.isValid();
-//   return !guid.isEmpty();
-}
+//inline bool isValidGuid(const Bstr& str)
+//{
+//   Guid guid(str);
+//   return guid.isValid();
+////   return !guid.isEmpty();
+//}
 
 } /* namespace com */
Index: /trunk/src/VBox/Main/src-client/ConsoleImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/src-client/ConsoleImpl.cpp	(revision 44090)
+++ /trunk/src/VBox/Main/src-client/ConsoleImpl.cpp	(revision 44091)
@@ -3177,5 +3177,5 @@
 {
 #ifdef VBOX_WITH_USB
-    CheckComArgExpr(aId, Guid(aId).isValid() == true);
+    CheckComArgExpr(aId, Guid(aId).isValid());
     CheckComArgOutPointerValid(aDevice);
 
@@ -3489,5 +3489,5 @@
 STDMETHODIMP Console::DeleteSnapshot(IN_BSTR aId, IProgress **aProgress)
 {
-    CheckComArgExpr(aId, Guid(aId).isValid() == true);
+    CheckComArgExpr(aId, Guid(aId).isValid());
     CheckComArgOutPointerValid(aProgress);
 
@@ -3512,5 +3512,5 @@
 STDMETHODIMP Console::DeleteSnapshotAndAllChildren(IN_BSTR aId, IProgress **aProgress)
 {
-    CheckComArgExpr(aId, Guid(aId).isValid() == true);
+    CheckComArgExpr(aId, Guid(aId).isValid());
     CheckComArgOutPointerValid(aProgress);
 
@@ -3535,6 +3535,6 @@
 STDMETHODIMP Console::DeleteSnapshotRange(IN_BSTR aStartId, IN_BSTR aEndId, IProgress **aProgress)
 {
-    CheckComArgExpr(aStartId, Guid(aStartId).isValid() == true);
-    CheckComArgExpr(aEndId, Guid(aEndId).isValid() == true);
+    CheckComArgExpr(aStartId, Guid(aStartId).isValid());
+    CheckComArgExpr(aEndId, Guid(aEndId).isValid());
     CheckComArgOutPointerValid(aProgress);
 
Index: /trunk/src/VBox/Main/src-server/HostImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/src-server/HostImpl.cpp	(revision 44090)
+++ /trunk/src/VBox/Main/src-server/HostImpl.cpp	(revision 44091)
@@ -1538,5 +1538,5 @@
 {
 #ifdef VBOX_WITH_USB
-    CheckComArgExpr(aId, Guid (aId).isValid() == true);
+    CheckComArgExpr(aId, Guid (aId).isValid());
     CheckComArgOutPointerValid(aDevice);
 
Index: /trunk/src/VBox/Main/src-server/MachineImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/src-server/MachineImpl.cpp	(revision 44090)
+++ /trunk/src/VBox/Main/src-server/MachineImpl.cpp	(revision 44091)
@@ -1001,5 +1001,5 @@
     // never be found by findMachine()
     Guid test(aName);
-    //if (test.isNotEmpty())
+
     if (test.isValid())
         return setError(E_INVALIDARG,  tr("A machine cannot have a UUID as its name"));
Index: /trunk/src/VBox/Main/src-server/MachineImplCloneVM.cpp
===================================================================
--- /trunk/src/VBox/Main/src-server/MachineImplCloneVM.cpp	(revision 44090)
+++ /trunk/src/VBox/Main/src-server/MachineImplCloneVM.cpp	(revision 44091)
@@ -1131,5 +1131,7 @@
                             {
                                 strSrcTest = strSrcTest.substr(1, strSrcTest.length() - 2);
-                                if (isValidGuid(strSrcTest))
+                                
+                                Guid temp_guid(strSrcTest);
+                                if (temp_guid.isValid() && !temp_guid.isZero())
                                     strNewName = Utf8StrFmt("%s%s", newId.toStringCurly().c_str(), RTPathExt(strNewName.c_str()));
                             }
Index: /trunk/src/VBox/Main/src-server/MediumImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/src-server/MediumImpl.cpp	(revision 44090)
+++ /trunk/src/VBox/Main/src-server/MediumImpl.cpp	(revision 44091)
@@ -2061,5 +2061,5 @@
                                     ComSafeArrayOut(BSTR, aSnapshotIds))
 {
-    CheckComArgExpr(aMachineId, Guid(aMachineId).isValid() == true);
+    CheckComArgExpr(aMachineId, Guid(aMachineId).isValid());
     CheckComArgOutSafeArrayPointerValid(aSnapshotIds);