Parallels Freeze after Sleep Solved I purchased a new MacBook Air 13" running OSX Lion this summer, with Parallels 6 and Windows 7 Ultimate, and I experienced the same problems as other writers in this thread. One consistently reproducible problem was to start MS Word with Windows 7 running in full screen mode and then close the lid of the computer or make it sleep from the Apple menu. The whole machine would always freeze. I opened up a support request to Parallels and I was advised to upgrade to Parallels 7. That solved the problem with Word and the request was closed. Later on, however, I experienced the computer freezing intermittently on resume from sleep with Parallels running when the computer was asleep overnight. Recalling what happens with my Windows 7 laptop when I close the lid, it occurred to me that the problem might have something to do with the hibernation mode. The Windows 7 laptop goes into a shallow sleep for a brief period and then, if it is not reactivated, it goes into a deep hibernation in which the contents of the memory are written to disk and power to RAM is cut off. It occurred to me that something like that might be happening on the MacBook. Parallels was resuming just fine if the computer was brought out of sleep immediately, but it was freezing if the computer was allowed to sleep for more than an hour or so. Investigating OSX sleep modes, I discovered that there is a similar form of hibernation on the Mac that is enabled by default and that writes the contents of RAM to disk. My solution was to change the sleep mode of OSX from mode 3, which is the default mode on computers after 2005, to mode 0, which keeps the RAM powered up until the computer wakes. Instructions for doing this can be found here: http://www.macworld.com/article/53471/2006/10/sleepmode.html After making this change I have had no further problems with the computer freezing after resuming from sleep with Parallels running. The disadvantage of this solution is that the computer sleeps in a higher power sleep state, which causes more battery drain, and if the battery does fail then anything in RAM is lost. But I consider that a small price to pay for being able to make my MacBook sleep without shutting down Parallels. I have no idea what Parallels support is currently saying about this problem. I haven't contacted them about it. But I can report that this solution works for me. I've been using it for a couple of months now with the setup described above: 2011 MacBook Air, OSX Lion, Parallels 7 in full screen mode, Windows 7 Ultimate. The only other problem I've experienced is a problem with the Windows 7 taskbar. After several sleep-resume cycles, closing a program leaves the taskbar icon for that program still highlighted, and reclicking on the icon will not reopen the program. The only solution is to reboot Windows. On the MacBook Air, with its solid state hard drive, this is fairly quick. But it is something Parallels ought to look into.