How to Free Up Space on Your Mac Without Deleting Photos

Your Mac is running low on storage but you don't want to lose your photos. Here's how to free up space on your Mac without deleting a single image.

MacBook storage bar full

If your Mac is running low on space and photos are a big part of the problem, you have more options than you think. You can free up significant storage without deleting a single photo — just moving where they live. Here's how to free up space on your Mac without losing any photos.

Why Photos Take Up So Much Mac Storage

A few things compound the problem:

iCloud optimisation off: If your Photos settings are set to "Download Originals to this Mac," every photo you've ever taken is sitting on your Mac's internal storage, full resolution, taking up your entire iCloud library's worth of space.
Photos library on internal storage: Even if you use Optimise Mac Storage, the Photos library file (the .photoslibrary bundle) lives on your Mac by default.
Large videos: A single 4K video can be 500MB–2GB. A few dozen of these from a trip in 2022 can be eating 20–30GB of your drive.

Understanding the source helps you choose the right fix.

Method 1 — Export Photos to an External Drive

The cleanest solution: move your entire iCloud photo library to an external drive and let iCloud hold lightweight previews only.

Migrate Moments for Mac makes this straightforward:

Connect an external SSD with enough free space (1–2TB drives cost around $100)
Open Migrate Moments — it scans your Photos library
Set your export destination to the external drive
Click Export — it downloads originals from iCloud directly to the drive, bypassing your Mac's internal storage
Once verified, delete the exported photos from iCloud to reclaim that space

After export, your Mac's internal storage drops dramatically — and your photos are safely on the external drive in original quality. For the full process, see our guide on how to export iCloud photos to an external hard drive on Mac.

Method 2 — Enable "Optimise Mac Storage"

If you don't have an external drive yet, this is the fastest fix:

Open Photos on your Mac
Go to Photos → Settings → iCloud
Select Optimise Mac Storage

With this enabled, macOS automatically replaces full-resolution originals with smaller thumbnails when your Mac starts running low on space. The originals stay in iCloud and download on demand when you open them.

This can recover tens of gigabytes on a large library. The trade-off: you need internet access to view full-resolution versions of older photos, and browsing your library can be slower.

Method 3 — Move the Photos Library to the External Drive

If you have an external drive you keep connected most of the time, you can move your entire Photos library there:

Quit Photos
Find your Photos Library in Finder — usually in ~/Pictures/Photos Library.photoslibrary
Drag it to your external drive
Hold Option and open Photos — click Choose Library and navigate to the external drive
In Photos → Settings → General, click Use as System Photo Library if prompted

This frees up exactly as much space as your Photos library uses — often 50–200GB for larger collections. The downside: Photos is slower when the drive isn't connected, and you need to remember to connect it before opening Photos.

Method 4 — Delete Optimised Videos You Don't Need

Videos are the biggest single category of space usage for most people. Go to Photos → Albums → Videos, sort by file size, and delete anything you've already watched or shared and don't need.

Combined with optimised storage, deleting 10–20 old videos can free up 5–15GB immediately.

Method 5 — Clean Up the "System Data" Category

If your Mac's storage analyser shows a large "System Data" category, this often includes:

Time Machine snapshots (automatic local backups — macOS eventually clears these)
App caches
Log files

For Photos specifically, old iPhone backups in iTunes/Finder can be enormous. Go to Finder → [Your iPhone] → Manage Backups and delete old backups you no longer need.

How Much Space Can You Recover?

Method	Typical space recovered
Export to external drive + delete from iCloud	20–500GB (entire library)
Enable Optimise Mac Storage	10–100GB
Move Photos library to external drive	Full library size
Delete old videos	5–30GB

The Best Approach for Large Libraries

If your iCloud library is over 50GB, the combination that works best:

Export originals to an external drive using Migrate Moments — this is your permanent backup
Enable Optimise Mac Storage in Photos settings — this keeps lightweight previews on your Mac
Delete from iCloud any photos that are safely on the external drive — optional, but this saves your iCloud storage bill too

After this, your Mac reclaims most of the space your photos were using, you have a physical backup, and your Photos app still works normally for viewing and editing.

Free Up Space on Your Mac With Migrate Moments

Migrate Moments for Mac is the fastest path to recovering your Mac's storage without deleting photos. It exports your iCloud originals directly to an external drive in smart batches — no manual steps, no filling up your Mac. Free to download and scan your library before committing.

Frequently Asked Questions

If I enable Optimise Mac Storage, are my photos still safe? Yes — the originals stay in iCloud. The optimised thumbnails on your Mac are just a local preview. As long as iCloud is active and you're paying for enough storage, your photos are safe.

Will the Photos app still work if I move the library to an external drive? Yes, as long as the external drive is connected. If you open Photos without the drive, it shows a limited offline view.

Does iCloud Photos count toward my Mac's storage? Yes — when set to "Download Originals," iCloud photos live on your Mac's internal storage. Switching to "Optimise Mac Storage" stops this. Migrate Moments also downloads directly to an external drive, bypassing internal storage.

How do I check what's using my Mac storage? Go to Apple Menu → About This Mac → More Info → Storage. This breaks down usage by category. Photos, System Data, and Applications are usually the top three.

Can I recover space without an external drive? Yes — enable Optimise Mac Storage in Photos settings. This is the free option. You'll recover less than an export to an external drive, but it requires no additional hardware.