Index: /trunk/src/VBox/Additions/x11/VBoxClient/main.cpp
===================================================================
--- /trunk/src/VBox/Additions/x11/VBoxClient/main.cpp	(revision 50450)
+++ /trunk/src/VBox/Additions/x11/VBoxClient/main.cpp	(revision 50451)
@@ -236,5 +236,5 @@
     while (true)
     {
-        if (hFile)
+        if (hFile != NIL_RTFILE)
             checkVTSysfs(hFile, cVT);
         /* The only point of this loop is to trigger the I/O error handler if