Setup: I have two monitors. The "built in" on my MBP 15" (1440x900) and a flat panel 1600x1200 external. I almost always put Parallels into coherence mode on the "built in" screen but limit it to just that screen (so it's not trying to span both displays). If it matters, the screens are set to be "offset" in my OS X display preferences since the external sits higher up than the built in. (That way my mouse moves in a straight line between the two monitors.) Problem: I frequently (at least once a day) get an error in Parallels about not enough video memory, try increasing it. This only seems to happen when my screens go to sleep and then wake back up. The exact error is: "The Screen resolution in the guest OS cannot be set because it is low on video memory. To increase the amount of video memory, shutdown the virtual machine, set new virtual machine video memory size (Edit Configuration -> Memory -> Video Memory)." Observations: When this happens, I notice that my /var/log/windowserver.log file starts filling with errors like: Mar 05 09:46:34  kCGErrorIllegalArgument: _CGXCacheMergeShmem: Invalid mergeShmemID (672) Mar 05 09:48:11  kCGErrorIllegalArgument: _CGXCacheMergeShmem: Invalid mergeShmemID (3950) I have to leave coherence mode or those errors will continue to occur. Once I leave coherence mode they seem to stop. If I try to re-enter coherence mode, they come back. Any suggestions on what I can try to fix the problem and/or when Parallels will actually work as advertised?