diff -up VirtualBox-6.1.4/src/VBox/Additions/x11/VBoxClient/display-svga-x11.cpp~ VirtualBox-6.1.4/src/VBox/Additions/x11/VBoxClient/display-svga-x11.cpp

--- VirtualBox-6.1.4/src/VBox/Additions/x11/VBoxClient/display-svga-x11.cpp~	2020-02-18 18:13:08.000000000 +0100

+++ VirtualBox-6.1.4/src/VBox/Additions/x11/VBoxClient/display-svga-x11.cpp	2020-03-03 16:27:49.947341705 +0100

@@ -100,16 +100,19 @@ static void x11Connect(struct X11CONTEXT

     {

         XCloseDisplay(pContext->pDisplay);

         pContext->pDisplay = NULL;

+        return;

     }

     if (!XRRQueryExtension(pContext->pDisplay, &pContext->hRandREventBase, &pContext->hRandRErrorBase))

     {

         XCloseDisplay(pContext->pDisplay);

         pContext->pDisplay = NULL;

+        return;

     }

     if (!XRRQueryVersion(pContext->pDisplay, &pContext->hRandRMajor, &pContext->hRandRMinor))

     {

         XCloseDisplay(pContext->pDisplay);

         pContext->pDisplay = NULL;

+        return;

     }

     pContext->rootWindow = DefaultRootWindow(pContext->pDisplay);

 }