SYMPTOMSYou have decided to change a Parallels Desktop 6 virtual machine (which was created in Parallels Desktop versions 3, 4 or 5) back to one of the previous versions of Parallels Desktop (also known as downgrading) and you cannot run it after that.
CAUSEIt is possible that you used the “encrypt” function in Parallels Desktop 6 for Mac. Encrypted Virtual Machines cannot be downgraded to earlier versions of Parallels Desktop.
RESOLUTIONYou'll need to decrypt the virtual machine before downgrading.
Follow these steps:
- If you have removed Parallels Desktop 6, reinstall it.
- Decrypt the virtual machine (in the virtual machine configuration go to 'Options' and choose 'Security')
- Uninstall Parallels Desktop 6.
- Install the previous version of Parallels Desktop you want (version 3, 4 or 5)
- Launch your virtual machine.