Use your operating system's search feature to search all hard disks for files whose name ends with .LRCAT
Double-click on each one found to open it and see if it is the one you are looking for
I tried and is not letting me either. See the message that I got.
This is a different problem. You need to go to the folder that contains this catalog file, and then find a file whose name ends with .LOCK. Delete the .LOCK file. Do not delete anything else.
I was able to get my old catalog. You are a genius!
What was the problem?
Just some info on what dj_paige posted.
When you open a Catalog File in Lightroom, Lightroom creates a temporary file with the same name as the catalog file with a .lock (LOCK) extension, this file prevents any other use of the Catalog File. When you quit the Lightroom application normally the .lock is removed from the Lightroom folder.
However if Lightroom is shut down unexpectedly e.g. power loss, application or OS crash the .lock file will remain in place and prevent Lightroom from opening the Catalog file.
In addition you should mark the post by dj as the correct answer.
Thank you DdeGannes!
I appreciate the explanation. I forgot to mark the correct answer. I will be aware the next time. Have a great night