Index: /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPWddm.cpp
===================================================================
--- /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPWddm.cpp	(revision 84324)
+++ /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPWddm.cpp	(revision 84325)
@@ -3466,4 +3466,5 @@
                     vboxWddmDisplaySettingsCheckPos(pDevExt, i);
                 }
+                Status = STATUS_SUCCESS;
                 break;
             }
Index: /trunk/src/VBox/Additions/WINNT/VBoxTray/VBoxDispIf.cpp
===================================================================
--- /trunk/src/VBox/Additions/WINNT/VBoxTray/VBoxDispIf.cpp	(revision 84324)
+++ /trunk/src/VBox/Additions/WINNT/VBoxTray/VBoxDispIf.cpp	(revision 84325)
@@ -33,19 +33,12 @@
 *   Defined Constants And Macros                                                                                                 *
 *********************************************************************************************************************************/
-#ifdef DEBUG_misha
+#ifdef DEBUG
 # define WARN(_m) do { \
-            Assert(0); \
-            Log(_m); \
-        } while (0)
-# define WARN_FUNC(_m) do { \
-            Assert(0); \
-            LogFunc(_m); \
+            AssertFailed(); \
+            LogRelFunc(_m); \
         } while (0)
 #else
 # define WARN(_m) do { \
-            Log(_m); \
-        } while (0)
-# define WARN_FUNC(_m) do { \
-            LogFunc(_m); \
+            LogRelFunc(_m); \
         } while (0)
 #endif
@@ -585,5 +578,5 @@
     }
 
-    return hr;
+    return ERROR_NOT_SUPPORTED;
 }
 
@@ -693,5 +686,5 @@
         else
         {
-            WARN_FUNC(("GetModuleHandle(USER32) failed, err(%d)\n", GetLastError()));
+            WARN(("GetModuleHandle(USER32) failed, err(%d)\n", GetLastError()));
             err = ERROR_NOT_SUPPORTED;
         }
@@ -699,5 +692,5 @@
     else
     {
-        WARN_FUNC(("can not switch to VBOXDISPIF_MODE_WDDM, because os is not Vista or upper\n"));
+        WARN(("can not switch to VBOXDISPIF_MODE_WDDM, because os is not Vista or upper\n"));
         err = ERROR_NOT_SUPPORTED;
     }
@@ -782,5 +775,5 @@
     else
     {
-        WARN(("VBoxTray: pfnD3DKMTEscape failed Status 0x%x\n", Status));
+        WARN(("VBoxTray: pfnD3DKMTEscape(0x%08X) failed Status 0x%x\n", pEscape->escapeCode, Status));
         winEr = ERROR_GEN_FAILURE;
     }
@@ -1014,5 +1007,5 @@
         if (!RegisterClassEx(&wc))
         {
-            WARN_FUNC(("RegisterClass failed, winErr(%d)\n", GetLastError()));
+            WARN(("RegisterClass failed, winErr(%d)\n", GetLastError()));
             hr = E_FAIL;
         }
@@ -1037,5 +1030,5 @@
         else
         {
-            WARN_FUNC(("CreateWindowEx failed, winErr(%d)\n", GetLastError()));
+            WARN(("CreateWindowEx failed, winErr(%d)\n", GetLastError()));
             hr = E_FAIL;
         }
@@ -1052,5 +1045,5 @@
 
     DWORD winErr = GetLastError();
-    WARN_FUNC(("DestroyWindow failed, winErr(%d) for hWnd(0x%x)\n", winErr, hWnd));
+    WARN(("DestroyWindow failed, winErr(%d) for hWnd(0x%x)\n", winErr, hWnd));
 
     return HRESULT_FROM_WIN32(winErr);
@@ -1099,5 +1092,5 @@
     {
         DWORD winErr = GetLastError();
-        WARN_FUNC(("SetEvent failed, winErr = (%d)", winErr));
+        WARN(("SetEvent failed, winErr = (%d)", winErr));
         HRESULT hrTmp = HRESULT_FROM_WIN32(winErr);
         Assert(hrTmp != S_OK); NOREF(hrTmp);
@@ -1204,5 +1197,5 @@
         {
             DWORD winErr = GetLastError();
-            WARN_FUNC(("CreateThread failed, winErr = (%d)", winErr));
+            WARN(("CreateThread failed, winErr = (%d)", winErr));
             hr = HRESULT_FROM_WIN32(winErr);
             Assert(hr != S_OK);
@@ -1213,5 +1206,5 @@
     {
         DWORD winErr = GetLastError();
-        WARN_FUNC(("CreateEvent failed, winErr = (%d)", winErr));
+        WARN(("CreateEvent failed, winErr = (%d)", winErr));
         hr = HRESULT_FROM_WIN32(winErr);
         Assert(hr != S_OK);
@@ -1708,10 +1701,13 @@
 {
     const VMMDevDisplayDef* pDispDef;
+    uint32_t i;
+
     VBOXDISPIF_OP Op;
-    DWORD winEr = ERROR_SUCCESS;
-    uint32_t i;
-    int iPath;
-
-    vboxDispIfOpBegin(pIf, &Op);
+    DWORD winEr = vboxDispIfOpBegin(pIf, &Op);
+    if (winEr != ERROR_SUCCESS)
+    {
+        WARN(("VBoxTray: vboxDispIfOpBegin failed winEr 0x%x", winEr));
+        return (winEr == ERROR_SUCCESS);
+    }
 
     for (i = 0; i < cDispDef; ++i)
@@ -1719,10 +1715,11 @@
         pDispDef = &paDispDef[i];
 
-        if (!(pDispDef->fDisplayFlags & VMMDEV_DISPLAY_DISABLED) &&
-             (pDispDef->fDisplayFlags | VMMDEV_DISPLAY_CX) ||
-             (pDispDef->fDisplayFlags | VMMDEV_DISPLAY_CY))
+        if (RT_BOOL(pDispDef->fDisplayFlags & VMMDEV_DISPLAY_DISABLED))
+            continue;
+
+        if (   RT_BOOL(pDispDef->fDisplayFlags & VMMDEV_DISPLAY_CX)
+            && RT_BOOL(pDispDef->fDisplayFlags & VMMDEV_DISPLAY_CY))
         {
             RTRECTSIZE Size;
-
             Size.cx = pDispDef->cx;
             Size.cy = pDispDef->cy;
@@ -1735,14 +1732,17 @@
 
     VBOXDISPIF_WDDM_DISPCFG DispCfg;
-
-    vboxDispIfWddmDcCreate(&DispCfg, QDC_ALL_PATHS);
+    winEr = vboxDispIfWddmDcCreate(&DispCfg, QDC_ALL_PATHS);
+    if (winEr != ERROR_SUCCESS)
+    {
+        WARN(("VBoxTray: vboxDispIfWddmDcCreate failed winEr 0x%x", winEr));
+        return (winEr == ERROR_SUCCESS);
+    }
 
     for (i = 0; i < cDispDef; ++i)
     {
+        pDispDef = &paDispDef[i];
+
         DISPLAYCONFIG_PATH_INFO *pPathInfo;
-
-        pDispDef = &paDispDef[i];
-        iPath = vboxDispIfWddmDcSearchPath(&DispCfg, pDispDef->idDisplay, pDispDef->idDisplay);
-
+        int iPath = vboxDispIfWddmDcSearchPath(&DispCfg, pDispDef->idDisplay, pDispDef->idDisplay);
         if (iPath < 0)
         {
@@ -1941,4 +1941,9 @@
 
     vboxDispIfOpBegin(pIf, &Op);
+    if (winEr != ERROR_SUCCESS)
+    {
+        WARN(("VBoxTray: vboxDispIfOpBegin failed winEr 0x%x", winEr));
+        return (winEr == ERROR_SUCCESS);
+    }
 
     for (id = 0; id < cDispDef; ++id)
@@ -1946,10 +1951,11 @@
         pDispDef = &paDispDef[id];
 
-        if (!(pDispDef->fDisplayFlags & VMMDEV_DISPLAY_DISABLED) &&
-            (pDispDef->fDisplayFlags | VMMDEV_DISPLAY_CX) ||
-            (pDispDef->fDisplayFlags | VMMDEV_DISPLAY_CY))
+        if (RT_BOOL(pDispDef->fDisplayFlags & VMMDEV_DISPLAY_DISABLED))
+            continue;
+
+        if (   RT_BOOL(pDispDef->fDisplayFlags & VMMDEV_DISPLAY_CX)
+            && RT_BOOL(pDispDef->fDisplayFlags & VMMDEV_DISPLAY_CY))
         {
             RTRECTSIZE Size;
-
             Size.cx = pDispDef->cx;
             Size.cy = pDispDef->cy;
@@ -2322,5 +2328,5 @@
 #endif
         default:
-            WARN_FUNC(("unknown mode (%d)\n", pIf->enmMode));
+            WARN(("unknown mode (%d)\n", pIf->enmMode));
             return ERROR_INVALID_PARAMETER;
     }
@@ -2341,5 +2347,5 @@
 #endif
         default:
-            WARN_FUNC(("unknown mode (%d)\n", pIf->enmMode));
+            WARN(("unknown mode (%d)\n", pIf->enmMode));
             return ERROR_INVALID_PARAMETER;
     }
@@ -2519,5 +2525,5 @@
 #endif
         default:
-            WARN_FUNC(("unknown mode (%d)\n", pIf->enmMode));
+            WARN(("unknown mode (%d)\n", pIf->enmMode));
             return ERROR_INVALID_PARAMETER;
     }
@@ -2545,5 +2551,5 @@
             if (!fSupported)
             {
-                WARN_FUNC(("pfnChangeDisplaySettingsEx function pointer failed to initialize\n"));
+                WARN(("pfnChangeDisplaySettingsEx function pointer failed to initialize\n"));
                 err = ERROR_NOT_SUPPORTED;
             }
@@ -2551,5 +2557,5 @@
         else
         {
-            WARN_FUNC(("failed to get USER32 handle, err (%d)\n", GetLastError()));
+            WARN(("failed to get USER32 handle, err (%d)\n", GetLastError()));
             err = ERROR_NOT_SUPPORTED;
         }
@@ -2557,5 +2563,5 @@
     else
     {
-        WARN_FUNC(("can not switch to VBOXDISPIF_MODE_XPDM, because os is not >= w2k\n"));
+        WARN(("can not switch to VBOXDISPIF_MODE_XPDM, because os is not >= w2k\n"));
         err = ERROR_NOT_SUPPORTED;
     }
@@ -2595,5 +2601,5 @@
             }
             else
-                WARN_FUNC(("failed to switch to XPDM_NT4 mode, err (%d)\n", err));
+                WARN(("failed to switch to XPDM_NT4 mode, err (%d)\n", err));
             break;
         case VBOXDISPIF_MODE_XPDM:
@@ -2606,5 +2612,5 @@
             }
             else
-                WARN_FUNC(("failed to switch to XPDM mode, err (%d)\n", err));
+                WARN(("failed to switch to XPDM mode, err (%d)\n", err));
             break;
 #ifdef VBOX_WITH_WDDM
@@ -2619,5 +2625,5 @@
             }
             else
-                WARN_FUNC(("failed to switch to WDDM mode, err (%d)\n", err));
+                WARN(("failed to switch to WDDM mode, err (%d)\n", err));
             break;
         }
@@ -2632,5 +2638,5 @@
             }
             else
-                WARN_FUNC(("failed to switch to WDDM mode, err (%d)\n", err));
+                WARN(("failed to switch to WDDM mode, err (%d)\n", err));
             break;
         }