diff --git a/examples/mac.c b/examples/mac.c
index 6ad0a54..2d335a4 100644
--- a/examples/mac.c
+++ b/examples/mac.c
@@ -464,6 +464,9 @@ ScreenInit(int argc, char**argv)
   rfbScreen->frameBuffer =
     (char *)CGDisplayBaseAddress(kCGDirectMainDisplay);
 
+  /* we cannot write to the frame buffer */
+  rfbScreen->cursor = NULL;
+
   rfbScreen->ptrAddEvent = PtrAddEvent;
   rfbScreen->kbdAddEvent = KbdAddEvent;