Today’s Question: I am in the process of cleaning my hard drives and consolidating backup files on a newer and faster external drive. In this process, I opened the folder where my weekly Lightroom backup catalog is stored. I was surprised that I have backups that date all the way back to 2010. My question is simple. When I use Lightroom’s weekly catalog backup feature am I creating an incremental file or an entirely complete backup?
Tim’s Quick Answer: The Lightroom catalog backup feature is a complete backup for the catalog file itself. Thus, you can absolutely delete older backup copies of the catalog.
More Detail: Lightroom now creates a compressed ZIP file that contains a copy of your catalog when you use the backup feature. Previous versions simply created a copy of the Lightroom catalog file (the “lrcat” file). However, the backup copy of the catalog compressed within the ZIP file is a full copy of the catalog file. Thus, to restore from a backup catalog you simply need to extract the “lrcat” file from the ZIP file, and then open the “lrcat” file in Lightroom.
It is worth noting, by the way, that in some cases the catalog file contained within the ZIP file will be larger than the “master” copy of your Lightroom catalog. This can be a little alarming if you extract the backup catalog from the ZIP and find that the file size differs from the size of the catalog you backed up.
However, the larger backup file size relates to the option to optimize the catalog after the backup is complete. With this option enabled the catalog will first be backed up, creating a backup copy that will be the exact same size as the existing catalog file (though compressed without loss into a ZIP file that will have a smaller file size). Then the master catalog will be optimized, which will often result in a smaller file size by cleaning up unnecessary records in the catalog file.
Because each backup of your catalog created by Lightroom is a complete catalog, there is no need to save multiple backup copies from the standpoint of being able to restore from a backup copy. Of course, you may want to retain a few backup copies from different dates as a precautionary measure, but older copies of your catalog can be deleted safely when you have deemed those additional backup copies are not needed.