If you have Lion’s FileVault2 enabled, and are running Parallels, you may experience an issue where your Mac reboots itself every time it is turned on or rebooted. The symptom is you turn your Mac on, it boots, then reboots… or you reboot your Mac, it boots, then reboots. To fix this, first make sure your Parallels is up to date. If updating Parallels doesn’t resolve the issue, turn FileVault2 off, reboot, then turn it back on.