Messages taking up space on your Mac? How to reduce it

Where Messages stores its data

Everything is in ~/Library/Messages. The conversations themselves are in a database file, which is small. The Attachments folder next to it holds the photos, videos and files, and that is where the space goes.

The folder is protected by macOS. Terminal can only measure it after you give it Full Disk Access in System Settings, under Privacy & Security. With that in place, the command below shows the total size and the size of the attachments. It only reads.

du -sh ~/Library/Messages ~/Library/Messages/Attachments 2>/dev/null

Check whether Messages in iCloud is on

Open Messages, choose Settings, then iMessage, and look for the Messages in iCloud setting. This decides what deleting means.

When it is on, your conversations are kept the same on every device signed in to your Apple Account. Delete a message, an attachment or a conversation on the Mac and it is removed from your iPhone and iPad too. When it is off, the Mac has its own copy, and deleting here affects only the Mac.

Messages in iCloud is a sync, not a space saver for the Mac. Turning it on does not by itself reduce what the Mac stores.

Delete the largest attachments from Storage

This is the quickest way to get space back without losing conversations.

• Open the Apple menu, choose System Settings, then General, then Storage.
• Click the info button next to Messages.
• The list shows attachments by size, largest first. Click one to preview it.
• Save anything you want to keep: drag it to a folder, or open it in Messages and save it to Photos.
• Select what you do not need and click Delete. The messages stay, and the attachment is removed from the conversation.

Delete attachments or whole conversations in Messages

To clear one conversation's media, open it in Messages and click the info button at the top. Scroll to the photos and files, select the ones you do not need and delete them.

To remove an entire conversation with everything in it, select it in the sidebar and choose Delete Conversation from the menu, or right-click it and choose Delete. Group chats that share a lot of video are usually the largest.

Recent versions of macOS keep deleted conversations for about 30 days. Choose View, then Recently Deleted, to restore them or delete them for good. Until then they still take space.

Limit how long messages are kept

By default Messages keeps everything forever. To put a limit on it, open Messages, choose Settings, then General, and change Keep messages from Forever to One Year or 30 Days.

This is a real deletion. Messages older than the limit, and their attachments, are removed, and with Messages in iCloud on, they are removed everywhere. Save photos and files you care about before changing it.

What not to do

Do not delete ~/Library/Messages or its Attachments folder in Finder while planning to keep using Messages. The database still refers to the files, so conversations end up with missing items, and with Messages in iCloud the result is hard to predict.

Do not treat the folder as a cache. These are your own photos, videos and documents. Often the copy in Messages is the only one.

Other message apps keep their own stores

WhatsApp, Telegram, Signal and Slack each keep downloaded media in their own folders under ~/Library, usually in Containers, Group Containers or Application Support. Clearing Messages does nothing to those.

Each app has its own storage settings for removing downloaded media, and that is the right place to do it. If one of those folders is large and you no longer use the app, uninstalling it together with its data returns the space.

Where Diskzy fits

Diskzy shows the Messages folder and its size on the disk map, and Search can list files by size or age, which helps you see whether attachments are a large share of your disk. Deleting them is best done from Messages or Storage, so conversations stay consistent.

For other chat apps you no longer use, Uninstall removes the app together with its support files, caches and containers, and everything goes to the Trash first.