Make room when your Mac says there's not enough space to update

Why it happens

A macOS update has to download first, then needs extra room to unpack and install. Small updates need a few gigabytes, but a big yearly upgrade can need 20 GB or more free. If your disk is nearly full, Software Update stops and tells you how much more space it needs.

How to fix it

1. Open System Settings, click General, then Storage. Give the bar at the top a moment to fill in.

   General›Storage

2. Start with the recommendations near the top, such as Store in iCloud, Optimize Storage and Empty Trash Automatically. Each one shows how much it can free.

3. Click the info button next to big categories like Documents to see your largest files, then delete the ones you don't need. Deleting here happens at once: it skips the Trash and can't be undone, so check each item before you click Delete.

   General›Storage›Documents

4. Old iPhone and iPad backups can take many gigabytes. Open iOS Files and delete backups for devices you no longer use. As with Documents, these are deleted straight away and can't be brought back.

   General›Storage›iOS files

5. Empty the Trash: Control-click the Trash in the Dock and choose Empty Trash. Deleted files only free space once the Trash is empty.

6. Restart your Mac. This clears temporary files and lets macOS release space it was holding on to.

7. Open General > Software Update and try the update again.

   General›Software Update

Still not fixed?

1. Still short of space? Copy big folders, like videos or old projects, to an external drive, check they open there, then delete them from your Mac.

2. Photos libraries are often the biggest thing on a Mac. If you use iCloud Photos, turn on Optimize Mac Storage in Photos settings to keep smaller copies on the Mac.

   Photos›Settings›iCloud›Optimize Mac Storage

3. If System Data looks huge, leave the Mac on and plugged in for a while after restarting. macOS clears its own caches and local backup snapshots when space runs low.

4. If you've freed plenty of space and the update still says there isn't enough, contact Apple Support. They can check the disk and help you install the update another way.