Symptoms
If you have VoiceOver utility enabled on your Mac and then switch Virtual Machine to Crystal mode, User Interface suddenly crashes, but Parallels Desktop continues running in background.Resolution
We are aware of the issue and work on it. As a workaround, please disable VoiceOver to be able to use Crystal mode in Parallels Desktop 5 Virtual Machine.To disable VoiceOver, open System Preferences > Universal Access, set Off option for VoiceOver.
For more information on Crystal mode, please check Parallels Desktop 5 documentation:
Crystal Mode
Note: Some customers reported that clearing check box Enable access for assistive devices in Universal Access pane helped to resolve the issue (this has not been reproduced by Parallels).