Index: kwin/workspace.cpp
===================================================================
--- kwin/workspace.cpp.orig
+++ kwin/workspace.cpp
@@ -59,6 +59,17 @@ KSelectionOwner* kompmgr_selection;
 
 bool allowKompmgrRestart = TRUE;
 
+bool supportsCompMgr()
+{
+    int i;
+
+    bool damageExt = XQueryExtension(qt_xdisplay(), "DAMAGE", &i, &i, &i);
+    bool compositeExt = XQueryExtension(qt_xdisplay(), "Composite", &i, &i, &i);
+    bool xfixesExt = XQueryExtension(qt_xdisplay(), "XFIXES", &i, &i, &i);
+
+    return damageExt && compositeExt && xfixesExt;
+}
+
 // Rikkus: This class is too complex. It needs splitting further.
 // It's a nightmare to understand, especially with so few comments :(
 
@@ -199,6 +210,9 @@ Workspace::Workspace( bool restore )
     connect( kapp->desktop(), SIGNAL( resized( int )), SLOT( desktopResized()));
 #endif
 
+    if (!supportsCompMgr())
+        options->useTranslucency = false;
+
     // start kompmgr - i wanted to put this into main.cpp, but that would prevent dcop support, as long as Application was no dcop_object
     if (options->useTranslucency)
         {