How to update macOS when you do not have enough space

By Pruneo TeamPublished: October 28, 2026Updated: October 28, 2026

You open Software Update, click Update Now, and your Mac tells you there is not enough space. This guide follows what Apple recommends and puts it in order, from the safest and fastest steps to the ones that need more care, so you can install the update without deleting anything important.

What Apple says

• In If an error occurs when you update or install macOS, Apple says that if the message says your Mac does not have enough space, you need to free up storage space.
• In How to download and install macOS, Apple explains that Software Update is the fastest way and that it can use less space than other methods.
• In How to free up storage space on your Mac, Apple adds that starting up in safe mode clears some system caches and can give you the space you need to complete a task, such as installing a macOS update.

So you do not need a separate installer. Free up space and try again from System Settings > General > Software Update.

How much space you need

Apple does not publish a fixed number. The installer needs quite a bit more than the download size, because it has to be unpacked before it installs. And in macOS 27 you need to add something else: after the update, the system downloads the Apple Intelligence models, which Apple says take up to 14 GB. We explain it in How much space Apple Intelligence uses on macOS 27.

Free up a bit more than the minimum. If you end up right at the limit, the Mac will be slow for the next few days and you will not be able to save new files.

Step 1: see what uses the most space

Open System Settings > General > Storage. The bar shows each category, and below it there is a list with the size of each one. Click the info button next to a category to see its files.

If you prefer Terminal, this command only reads and gives you the size of your main folders:

du -sh ~/Downloads ~/Desktop ~/Movies ~/Library 2>/dev/null

Step 2: the fastest and safest steps

1. Empty the Trash. Apple reminds you that the space is not free until you empty it. Before that, check that there is nothing you want to get back.
2. Review Downloads. Old .dmg installers, videos and compressed files often add up to several gigabytes. Sort by size in the Finder (View > as List and click Size).
3. Delete old iPhone or iPad backups. In Storage, open iOS Files to see each backup with its date and delete the ones you no longer need. Keep at least the most recent one for each device if you do not have an iCloud backup.
4. Delete downloaded movies and shows that you can download again from the TV or Music app.

Step 3: start up once in safe mode

Follow Apple’s steps in Start up your Mac in safe mode. When you enter, macOS clears some system caches. Then restart normally and try to update again. These caches are created again when needed, so you lose nothing.

Step 4: if you still need space

• Move large libraries to an external drive. Apple suggests it for the Photos library and the iMovie library. Do it with the app closed, and open the library from the new drive before you delete the original.
• Uninstall apps you do not use. Some of them, like games or video editing apps, take tens of gigabytes.
• Check System Data. Time Machine local snapshots and user caches count there. We explain it in What is System Data on Mac.
• Use iCloud if you have it. The Storage recommendations let you store files in iCloud: the ones you have not opened in a while stay in the cloud and download when you need them.

After you update

Free space can drop during the first few days. macOS keeps temporary installation files, an extra Time Machine local snapshot and, in macOS 27, the Apple Intelligence download. Wait a day or two before you clean again: a good part of that space comes back on its own.

Summary

1. Apple recommends freeing up space and using Software Update, which uses less space.
2. Start with the Trash, Downloads and old iPhone backups.
3. Start up once in safe mode to clear system caches.
4. If you need more, move libraries to an external drive or uninstall apps.
5. Leave room for Apple Intelligence and wait a day after updating.

For the complete cleaning plan, read How to free up space on Mac, or download Pruneo for free.

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