My Lightroom won't open. I just get a message that says "The Lightroom catalog named "Lightroom 5 Catalog" cannot be opened because another application already has it opened." The catalog is not open.
My computer crashed and now it won't open.
Using your system browser (Windows Explorer or Finder), open the folder containing your catalog and look for a file with the .lock extension. You will need to delete that file, and then Lightroom will start normally. The file will have the same name as the catalog you have been using, but will have the different extension. Only delete the file with the .lock extension.
Thank you! !!!!
You are welcome. That lock file is created by the Lightroom catalog. When Lightroom shuts down normally the file is automatically deleted. But since your computer crashed, the file was left behind.