I was working in Lightroom - got an error - shut it down and shut the computer down and restarted - now when i pull up lightroom it says "The Lightroom catalog named "Lightroom catalog" cannot be opened because another application has it opened."
Quit the other copy of Lighroom before trying to launch
Then the choices are "choose a different catalog, Continue, Exit
I don't have it pulled up anywhere else as far as I know ???
With the File Explorer, go to the folder that contains the Lightroom Catalog. (usually a folder named Lightroom or Lightroom Catalog inside the Pictures folder.)
Delete the file that has the extension .LOCK. It'll be named something like "Lightroom Catalog v10.lrcat.lock"
Do not delete anything else.
The lock file is only present when LR is running, and will normally be deleted when you close Lightroom, but if it's not closed down properly, the lock file may not be deleted, and you'll get this somewhat confusing error message.