Index: /trunk/src/VBox/Additions/WINNT/Installer/VBoxGuestAdditions.nsi
===================================================================
--- /trunk/src/VBox/Additions/WINNT/Installer/VBoxGuestAdditions.nsi	(revision 38934)
+++ /trunk/src/VBox/Additions/WINNT/Installer/VBoxGuestAdditions.nsi	(revision 38935)
@@ -651,5 +651,5 @@
 !endif
 
-vista: ; Windows Vista / Windows 7
+vista: ; Windows Vista / Windows 7 / Windows 8
 
   ; Copy some common files ...
@@ -963,4 +963,11 @@
 
 !if $%VBOX_WITH_WDDM% == "1"
+    ; If we're running Windows 8 we always need the WDDM driver
+    ; -- so just print a hint about the required VRAM size and bail out
+    ${If} $g_strWinVersion == "8"
+      MessageBox MB_ICONINFORMATION|MB_OK $(VBOX_COMPONENT_D3D_HINT_VRAM) /SD IDOK
+      goto exit
+    ${EndIf}
+
     ; If we're able to use the WDDM driver just use it instead of the replaced
     ; D3D components below
@@ -1003,5 +1010,7 @@
     ${EndIf}
   ${Else} ; D3D unselected again
-    StrCpy $g_bWithWDDM "false"
+    ${If} $g_strWinVersion != "8" ; On Windows 8 WDDM is mandatory
+      StrCpy $g_bWithWDDM "false"
+    ${EndIf}
   ${EndIf}
   Goto exit
Index: /trunk/src/VBox/Additions/WINNT/Installer/VBoxGuestAdditionsCommon.nsh
===================================================================
--- /trunk/src/VBox/Additions/WINNT/Installer/VBoxGuestAdditionsCommon.nsh	(revision 38934)
+++ /trunk/src/VBox/Additions/WINNT/Installer/VBoxGuestAdditionsCommon.nsh	(revision 38935)
@@ -512,9 +512,14 @@
 
 !if $%VBOX_WITH_WDDM% == "1"
-  ; If we're on a 32-bit Windows Vista / 7 we can use the WDDM driver
+  ; If we're on a 32-bit Windows Vista / 7 / 8 we can use the WDDM driver
   ${If} $g_strWinVersion == "Vista"
   ${OrIf} $g_strWinVersion == "7"
   ${OrIf} $g_strWinVersion == "8"
     StrCpy $g_bCapWDDM "true"
+  ${EndIf}
+  ; If we're on Windows 8 we *have* to use the WDDM driver, so select it
+  ; by default
+  ${If} $g_strWinVersion == "8"
+    StrCpy $g_bWithWDDM "true"
   ${EndIf}
 !endif