You uninstall Parallels Tools when you last boot the VM in PDM 3, that's the only way to uninstall them before conversion. When you launch the VM in PDM 8, it will be immediately converted, so you can't uninstall Parallels Tools in PDM 8 before conversion.
To avoid any problem, while still in PDM3:
* Defragment and run chkdsk (checkdisk) in PDM3.
* Uninstall Parallels Tools
* Eliminate/merge all snapshots in PDM3
* Be sure to correctly shut down the VM in PDM3, not suspended, no snapshots. Go to Start > Shut Down.
* Backup the VM.
Only now your VM is ready to be converted in the safest way possible.
Last edited: Feb 11, 2013