I am in a similar boat - installed MacOS Big Sur on my MacBook Pro. Since then I get the "To complete Parallels Desktop setup, please restart your Mac." error, and the same result of needing to Force Quit Parallels, and restarting the machine having no affect on the situation. I have submitted a technical report for this - ID 343418720. Hopefully we can get some information on/a resolution for the issue.
Last edited by a moderator: Jun 26, 2020