“The Lightroom catalog cannot be opened because another application already has it opened.”

Situation: You have a problem to run Lightroom with this error:
The Lightroom catalog cannot be opened because another application already has it opened.

Troubleshooting: delete *.lrcat.lock.
When Lightroom is running, it creates a *.lrcat.lock file next to the *.lrcat file. if Lightroom is not shut down properly, the *.lrcat.lock file remains in the same folder as the .lrcat file, which prevents Lightroom from opening. In this case, you may delete or rename *.lrcat.lock.

By default, Lightroom *.lrcat.lock is located in the following folders:

  • Windows: \Users\[user name]\Pictures\Lightroom
  • Mac OS: /Users/[user name]/Pictures/Lightroom

Note: Close Lightroom when you delete the
*.lrcat.lock.

Published by

Bob Lin

Bob Lin, MS-MVP, MCSE & CNE Data recovery, Windows OS Recovery, Networking, and Computer Troubleshooting on http://www.ChicagoTech.net How to Install and Configure Windows, VMware, Virtualization and Cisco on http://www.HowToNetworking.com