Catalog Backup Too Big


Today’s Question: I just started getting an error message in Lightroom indicating that my catalog is over 4GB and I need to use a third party utility to extract my catalog backup. I have plenty of hard drive space and have no need to do anything exotic. Need I worry about anything? I don’t understand the explanation linked to under “Learn More.”

Tim’s Quick Answer: The error you’re seeing relates to an issue with ZIP files over 4GB in size on the Macintosh operating system. The error is not a major issue, as there are a variety of tools that enable you to extract files from a ZIP file that is over 4GB in size.

More Detail: The basic issue here relates to some limitations with certain operating systems related to ZIP files (or files in general) over 4GB in size. The built-in support for ZIP files on the Macintosh platform does not extend to ZIP files over 4GB in size, in some cases reporting such ZIP files as being corrupted. As a workaround, you can use a third-party tool (rather than the operating system itself) to extract a backup of a catalog that exceeds 4GB. For example, StuffIt Expander ( provides broader compatibility for extracting compressed files.

Of course, this is only an issue when you need to actually restore your catalog from a backup. Hopefully that will never be an issue for any photographer. But when it does become necessary to restore from a backup, if your catalog backup is over 4GB in size you may need to use a third-party utility to extract the backup.

This file size issue is not a concern for most Windows users, and frankly it isn’t a major concern for Macintosh users. In this case it would be perfectly reasonable to turn on the “Don’t show again” checkbox in the alert dialog regarding the large catalog size, so that you won’t see this message in the future.