Clean up duplicate files on your NAS

31 May 2026 · 4 min read

A NAS is where copies pile up: phone backups, the same shoot from two drives, exports you copied twice. Here is how to clean up your Synology or QNAP without installing anything on the NAS.

Scan for free

Mount your NAS as a network drive

Make sure your NAS shows up as a network drive in Finder (over SMB or AFP). Once you see it in Finder, DupliFind can treat it like a regular folder.

You install nothing on the NAS itself. The scan runs on your Mac, the NAS only serves the files.

Scan several drives at once

Add your NAS, your external drive and a local folder in one go. DupliFind groups duplicates across all of those locations, so you instantly see which copy sits where.

Mind the scan time on big drives

A full NAS can hold a lot of files. Set a minimum file size, say 1 MB, so you do not waste time on tiny files.

Reading over the network is slower than a local drive. Start with a single folder to get a feel for it.

Clean up safely over the network

Here too one copy is kept in every group and deleted files move to a quarantine folder first. You can always go back.

Frequently asked questions

Does it work with Synology and QNAP?+

Yes. The brand does not matter. As long as the NAS shows up as a network drive in Finder, you can scan it.

Are my files uploaded through my Mac?+

No. DupliFind reads the files locally to compare them, but sends nothing to a server. Everything stays inside your own network.

Can I scan my NAS and external drive together?+

Yes. Add multiple folders and DupliFind finds duplicates across all locations.

Clean up your NAS

Mount your NAS in Finder, add the folder and see how much space you reclaim. Free to scan.