Help · Guides · Pangalin Space Manager

How to move big folders to an external drive, and put them back.

By Grant and Brad, who make Pangalin's apps · Updated 12 October 2026

Some of the biggest things on a Mac don't need to live on it: AI models, old projects, downloads, virtual machines. Pangalin Space Manager copies them to an external drive, checks every file, then leaves a shortcut in the old place so apps still find them while the drive is plugged in. Every move can be put back from History.

Before you start

A move is not a backup. After the move, the external drive holds the only copy. If you lose or erase that drive, the data is gone, and Time Machine won't back it up unless you back up that drive too.
The drive needs to be plugged in whenever an app needs those files. Unplugged, nothing is lost; the files just can't be opened until you reconnect.
Use an APFS-formatted drive if you can. Drives formatted MS-DOS (FAT) are refused, because they can't hold files over 4 GB. exFAT drives work but waste space and copy slowly with folders full of small files. To check, select the drive in Finder and choose File › Get Info.
Quit the app that uses the folder. Pangalin Space Manager skips anything whose app is running and tells you.

Move

Plug in the drive, then choose Go › Move to External (⌘3).
Under Ready to move, click a group (for example AI Models, Downloads, Dev or VMs) and tick what you want to move. Models in your own project folders are listed separately and never ticked for you.
Click Review and move …. If you haven't chosen a destination yet, choose a folder on the external drive.
Read the summary: the destination, the biggest items and what changes after the move. If what you picked shares its storage with copies that stay on your Mac (APFS clones, for example a duplicate of the same model), the summary says how little the move would free; from 3.48.1. Click Move, or Change destination….
Wait while it copies and verifies. The original is removed only after every file and byte has been checked. If anything goes wrong, the original is left untouched.

Items land in an Offloaded folder on the drive, sorted by type, with a Pangalin Space Manager Catalog.txt listing what's there. Pangalin Space Manager checks there's enough room on the drive first.

The Move to External screen: Ready to move groups such as AI Models, Libraries and Downloads, and the AI Models list with the Hugging Face cache and models in your own folders. — Move to External, with AI Models open. Personal model folders and the licence name are blurred. Pangalin Space Manager 3.48.0, 11 October 2026.

Photos, Music and app libraries

Libraries managed by an app, such as Photos, Music, Logic Pro sound content or Ableton Packs, must be moved by that app, or the library can break. Pangalin Space Manager doesn't move them in bulk. Open the library's row under Big libraries, each with its own route for the steps, an Open button for the app, and a link to the developer's own guide.

Put a move back

Plug in the drive the data was moved to.
Choose Go › History (⌘7).
Under Moves you can roll back, find the move and click Reinstate. It starts straight away.

Pangalin Space Manager copies the data back, checks it, removes the shortcut and sends the drive's copy to the Trash. Pangalin Space Manager checks there's room on your Mac first; if there isn't, nothing changes and the shortcut keeps working. To bring everything back, use Reinstate all. Putting things back is free, with or without a licence.

Just moved something by mistake? Edit › Undo Move of … (⌥⌘Z) undoes it straight away, while Pangalin Space Manager is open.

The History screen: totals freed and moved, and a Moves you can roll back list with a Reinstate button next to a moved folder. — History, with a move you can reinstate. The action log and the licence name are blurred. Pangalin Space Manager 3.48.0, 11 October 2026.

If the drive isn't plugged in

The Dashboard says “External drive missing” and lists how many moved items are on it. They're safe on the drive. Apps that need them won't find them until you reconnect it, and then everything works again.

Doing it by hand

You can copy a folder to a drive in Finder and delete the original, but apps that expect it in the old place will stop finding it. Pangalin Space Manager's shortcut (a symbolic link), its byte-for-byte check and the History record are what make a move safe to undo.

If the drive isn't connected

Moved files won't open until the drive is back, and apps that use them may say they're missing. Nothing is lost: the files are on the drive. Moved Files shows a card for each missing drive, listing what's on it. If the drive is plugged in but not mounted, click Mount …. An item marked Not on the drive is no longer where Pangalin Space Manager left it.

Related guides

Checked against Pangalin Space Manager 3.47.0, 10 October 2026. Screenshots from Pangalin Space Manager 3.48.0, 11 October 2026.