Lightroom Unexpected Error opening Catalog

Looking for some help here. I am currently running Lightroom Classic on a iMac with system 10.15.5. About every two days I try to open Lightroom and get Unexpected Error opening Catalog. It then gives me the option to repair and that fails. I have all of this on an external HD and backed up to another external HD. I have to then use one of the Lightroom backups but often I lose some of the edits. Any ideas why this is happening?

This has happened to me as well. Typically this means that the catalog you were editing on has failed, which unfortunately is not uncommon with Lightroom. I would go back to your backup catalogs and look for the last version that worked. Hope this helps!

Good Morning Peter Enich,
Sorry to hear about the Adobe Photoshop Lightroom Classic troubles. I am curious when you do get Lightroom to open what does the Optimize Catalog, or the internal Catalog Backup function, tell you? Will it complete successfully?

Also, where is your Lightroom Catalog? Is it on one of your external drives or on your internal? If it’s on the external what does the Apple Disk Utility First Aid report when you ask it check on the health of that drive?

David Marx

Hi David,

Thanks for the response. I have not had the error in a couple of days so I am working from memory here. When the error happens it says that it can’t open the catalog because it is corrupt. Then it asks me if I wish to repair it and I say yes. Then is says that it can’t complete the task or it fails. Don’t remember the exact wording. Not sure what the Optimize Catalog or Internal Catalog Backup function is. My fix has been to uncompress my latest back up made by Lightroom and use the new catalog that is formed when I uncompress that file.

The catalog is on a new external drive that I formatted for Mac. Disk First Aid says everything is great.



Good Morning Pete,

Uncompressing an Adobe Photoshop Lightroom Classic generated Catalog backup is an adequate workaround but I am still curious what is triggering the actual errors.
If I may suggest, there are two things that I would do if I were you:

  1. Try moving your Adobe Photoshop Lightroom Classic Catalog to your Mac’s internal hard drive. Unless you are low on internal drive space, or if you are working with both a laptop and desktop, then Catalog storage on the internal drive is likely to improve performance and reduce the odds that the external hard drive is triggering this problem.

  2. If you do not yet have robust backups in place for your new external hard drive, and your computer’s internal disk, then I urge you to do so. If needed follow the link below for more advice on this topic:

David Marx