How to Exclude Items from a Time Machine Backup to Shrink It

Your Time Machine backups are larger than they need to be because they include big folders you don’t need to protect — virtual machines, downloads, caches or media you store elsewhere.

Why: By default Time Machine backs up almost everything. Adding items to its exclude list keeps them out of every future backup, which makes backups smaller and faster and stretches the space on your backup disk.

Fix 1: Open the exclude list

1. Open Apple menu > System Settings > General > Time Machine.
2. Click Options.

You’ll see the list of items that shouldn’t be backed up. The backup disk itself is already on that list automatically.

Fix 2: Add items to exclude

1. Click the Add (+) button, then select one or more files or folders to exclude. You can also drag items into the list.
2. Good candidates: virtual-machine disk images, large Downloads contents, app caches, and any media library you already keep backed up elsewhere.
3. To stop excluding something later, select it in the list and click the Remove (–) button.
4. Click Done.

Future backups skip the excluded items immediately. Files already in older backups stay there until those backups age out or are deleted for space.

Fix 3: Decide what’s safe to exclude

• Safe to exclude: files you can re-download or that are backed up another way (streaming media, installers, cloud-synced folders).
• Don’t exclude: anything you’d be upset to lose, especially your Documents, Desktop and Pictures.

If your goal is to recover disk space generally rather than shrink backups, see also free up space when the startup disk is full.

FAQ

Does excluding a folder delete it from existing backups? No. It only stops future backups from including it. Old snapshots keep the data until they’re removed.

Will excluding files speed up backups? Yes — less data to copy and verify means faster backups and more headroom on the disk.

My backups are still huge. A first backup is always large. If the disk keeps filling, also see the Time Machine backup disk is full.

Sources: Apple Support — Exclude files from a Time Machine backup on Mac · Apple Support — Back up your Mac with Time Machine