diskDedupe 4+

I paid for this app for the specific purpose of cloning the internal drive of my Mac Mini to an external SSD in preparation for replacing the Mini's internal drive with the SSD. But this app doesn't do that. I misread the description so this is my fault. That said, the developer is first rate with a personal response and kind, helpful suggestions for getting a refund. In fact, I may well keep this app just for the excellent support...

We are sorry that you misread our product description as one for a disk cloning app. It is not and nowhere in our description it pretends to be.

If you bought software in the Apple App Store by accident, you can work with Apple Support to get a refund.

To help you with finding software for cloning disks we recommend looking into "Carbon Copy Cloner" or "SuperDuper" (both not available in the App Store though).

This works well when scanning reasonable amounts of files, up to a few million at least — it saves space and seems to be reliable. It’s cleaner and generally much faster than script-based solutions. The interface is bare-bones but easy to use.

However, I tried applying it to a much larger set (60 million files) and its memory requirements grew to 90 GB by the time I gave up 20 hours or so later (due to needing to actually use some of those files, and memory swapping eating into the SSD lifetime on my Fusion drive).

A .dedupCache file is created; is this used to avoid processing duplicate files again when rescanning? There’s scant documentation.

Thank you Anton for the feedback. Please check the new version 1.09.22 of diskDedupe. Based on your feedback we significantly reduced memory requirements especially for large disks. We have implemented a number of improvements to better handle low memory situations when deduplicating extremely large data sets.

You are right, the .dedupeCache file is created to speed up future runs of diskDedupe. You can delete it, if you want to.