Hello. LR Classic no longer opens on my iMac, since the update. It gets stuck on the splashscreen. MacOs Monterey 12.01. When I downgrade to LRC 10.4, it works fine. However I work between my iMac and my macbook, and my macbook is running 11.01 just fine, and the catalogs are incompatible.
Had LrC just closed without warning after that point, or gave a warning about already being opened, then I would assume the lock file did not get deleted the last time LrC terminated. This would be the case if LrC crashed, or you forced quit. You might want to check for that. In that case the splash screen would have closed.