Index: reactos/win32ss/user/user32/misc/display.c
===================================================================
--- reactos/win32ss/user/user32/misc/display.c	(revision 74270)
+++ reactos/win32ss/user/user32/misc/display.c	(working copy)
@@ -35,11 +35,18 @@
     UNICODE_STRING Device;
     DISPLAY_DEVICEW DisplayDeviceW;
 
-    if (!RtlCreateUnicodeStringFromAsciiz(&Device, (PCSZ)lpDevice))
+    if (lpDevice)
     {
-        SetLastError(ERROR_OUTOFMEMORY);
-        return FALSE;
+        if (!RtlCreateUnicodeStringFromAsciiz(&Device, (PCSZ)lpDevice))
+        {
+            SetLastError(ERROR_OUTOFMEMORY);
+            return FALSE;
+        }
     }
+    else
+    {
+        RtlInitUnicodeString(&Device, NULL);
+    }
 
     RtlZeroMemory(&DisplayDeviceW, sizeof(DISPLAY_DEVICEW));
     DisplayDeviceW.cb = sizeof(DISPLAY_DEVICEW);
@@ -69,7 +76,8 @@
                             NULL, NULL);
     }
 
-    RtlFreeUnicodeString(&Device);
+    if (lpDevice)
+        RtlFreeUnicodeString(&Device);
 
     return rc;
 }