Messages on iCloud taking up a lot of space on macOS

If you navigate to ~/Library/Messages you will see two folders:

• Attachments
• Caches

Over time, when using Messages on iCloud, these directories grow exponentially in size (mine was 27GB).

It seems like macOS doesn't automatically clear the Attachments and Caches folder.

Solution

You can manually delete the Attachments and Caches folder in Finder to clear space.

1. Open up Finder
2. Select the Go option in the toolbar on the top
3. Paste ~/Library/Messages
4. Press Return on the keyboard
5. Backup the Attachments and Caches folder to an external HDD
6. Delete the Attachments and Caches folder
7. Empty the Trash Can

Make sure to backup the Attachments and Caches folder to an external disk in a folder that contains the date (Messages_20250308).

Deleting the Attachments and Caches folder in ~/Library/Messages won't delete the message or attachment from iCloud; it just deletes the local attachment(s) on the macOS SSD while keeping the original file in iCloud.

I freed up 27GB on my macOS doing this.

If you open Messages after deleting the Attachments and Caches folder, the conversation will show a photo icon and a download icon if you wish to download it again from iCloud.

Request for Apple

macOS 16 should automatically clear the Attachments and Caches folder at ~/Library/Messages after 30 days when using Messages in iCloud. The Apple Photos app does this automatically on iOS and macOS.

Hopefully this helps everyone!

Cheers, M