How to free up Mac space without deleting your photos

A full drive often comes down to one folder: the Photos library. Years of pictures and 4K video add up to hundreds of gigabytes, and none of it feels deletable. The good news is that you do not have to delete any of it. You just need it to live somewhere other than the internal drive.

Check how much the library actually takes

Photos shows one number for the whole library, so start there. In DiskDude, scan your home folder and look for Photos Library.photoslibrary in the Top sizes view. It is treated as a single item, so you can see its full size without opening it.

If it is under 20 GB, this article will not help much. Look at caches and developer folders instead. If it is over 100 GB, keep reading.

Option 1: Optimize Mac Storage with iCloud Photos

If you already pay for iCloud storage, this is the simplest option.

1. Open Photos → Settings → iCloud.
2. Turn on iCloud Photos if it is not already on.
3. Select Optimize Mac Storage.

Photos uploads full-resolution originals to iCloud and keeps smaller versions on the Mac. Originals download when you open or edit them. The library shrinks gradually as macOS needs the space, so it may take a few days to see the effect.

You need enough iCloud storage for the full library. The 2 TB plan covers most people.

Option 2: Move the library to an external drive

If you would rather not pay for iCloud, move the library to an external SSD.

1. Quit Photos.
2. Copy Photos Library.photoslibrary from ~/Pictures to the external drive.
3. Hold Option while opening Photos and choose the library on the external drive.
4. Once you have confirmed everything is there, delete the copy in ~/Pictures.

The drive must be formatted as APFS or Mac OS Extended. Photos will not open a library on a drive formatted for Windows. The library is only available while the drive is connected, so this works best for a desktop Mac or a laptop that mostly stays at one desk.

Option 3: Split the library

Keep recent photos on the internal drive and archive older years to an external drive.

1. Create a new library on the external drive with File → New Library.
2. Import the older years into it from the original library.
3. Delete those years from the original library.

Photos only shows one library at a time, so switching between them means holding Option at launch. This suits people who rarely look back more than a year.

Videos outside Photos

Screen recordings, exported movies, and clips from cameras often sit in ~/Movies, ~/Desktop, or ~/Downloads rather than the Photos library. They are usually the largest individual files on a Mac and are easy to move to an external drive as plain files. The Age map view in DiskDude shows which ones you have not opened in over a year.

What not to do

• Do not delete the library to reclaim space after turning on iCloud Photos. The library is still the local cache, and deleting it triggers a full re-download.
• Do not store the only copy on one external drive. External drives fail. Keep a backup with Time Machine or a second copy.
• Do not move the library to a cloud-synced folder like Dropbox or Google Drive. Sync tools corrupt Photos libraries.