When I open a pdf and edit it (comments, delete pages, etc) and try to save it, I get the message "The file may be read-only, or another user may have it open. Please save the document with a different name or in a different folder." This happens even if I DO try to save to a different folder or name. I am using MAC with Big Sur OS v 11.2.3 and the latest update of Acrobat. This is a new problem
Is your file/asset is in a folder that is synced with Google Drive, Drop Box, One drive or the like? If yes simply quit the backup/sync utility and then hit save on the file. You may also try the following settings Go to Acrobat Pro > Preferences > General > uncheck Show online storage when saving files > OK and see if that works for you.