Index: /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPWddm.cpp
===================================================================
--- /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPWddm.cpp	(revision 74670)
+++ /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPWddm.cpp	(revision 74671)
@@ -40,5 +40,9 @@
 #define VBOXWDDM_DUMMY_DMABUFFER_SIZE (sizeof(VBOXCMDVBVA_HDR) / 2)
 
+#ifdef DEBUG
+DWORD g_VBoxLogUm = VBOXWDDM_CFG_LOG_UM_BACKDOOR;
+#else
 DWORD g_VBoxLogUm = 0;
+#endif
 
 /* Whether the driver is display-only (no 3D) for Windows 8 or newer guests. */