I updated LR classic yesterday and now cannot get into it. It keeps telling me that another application has it open?! I don't have another application open, I have rebooted twice, I have uninstalled and installed it again. Very frustrating, any help is appreciated. I am on a MacBook Pro
Using Finder, open the folder that contains your catalog and locate a file that has the same name as your catalog, but has a lock extension. That file has to be deleted. Apparently Lightroom shut down abnormally and left that file behind, and it will be necessary for you to delete it manually. Normally it is deleted automatically when Lightroom closes.