How to diff Photos Library backup against original (to check for corruption) It seems the official way to backup your Photos Library is to literally drag it from your OSX desktop onto your external storage. So I did that.

Now, I want to know how to do a diff between the new Photos Library  created on external disk and the original Photos Library on the OSX, before I delete it from my OSX forever.

How to do this using official Apple methods/utils or Linux CLI?
One note of caution, dragging photos to the desktop does a lossy export and you’ll lose all sorts of metadata and photo quality if you bypass the export functionality.

That being said, there is a tool that lets you merge / duplicate / check that two different libraries have the same or different photos (as well as the super useful deduplication features for which I pay gladly alone for this software).


https://fatcatsoftware.com/powerphotos/


There is a demo version you can try - so if there’s not another method, you can do far worse than starting with this app. It’s fast, reliable, updated and supported by the author and been around for quite many years.