LRCAT can't open, already open

[pinholeplus]

When trying to open lightroom, I get the message:

"

The Lightroom catalog named “LRCAT_102917-2-v10” cannot be opened because another application already has it opened."

I've delteted program and reopened it, to no avail. Tried to import catalopg into new catalog, but get the same message.

 I'm using Mac OS Big Sur.

[dj_paige · Accepted solution]

In Mac Finder, go to the folder where your catalog file is stored. There is a file whose name ends with .LOCK. Delete this .LOCK file. DO NOT DELETE ANYTHING ELSE.