Auto-Delete Old Messages on Mac (Keep 30 Days)

By default, Messages on a Mac keeps every conversation forever — every photo, video, voice memo, and GIF included. After a few years that's easily several gigabytes of chat history you'll never scroll back through. One setting flips Messages into cleanup mode: keep 30 days or one year, and it deletes the rest on its own.

Turn on auto-delete in Messages

1. Open Messages and choose Messages → Settings… from the menu bar (or press Cmd+,).
2. Click the General tab.
3. Change Keep messages from Forever to One Year or 30 Days.
4. Messages warns you that older conversations will be permanently deleted. Click through only when you're sure — see the caveats below first.

From then on, anything older than the window you picked is removed automatically, attachments included. If you're nervous, start with One Year; you can always tighten it to 30 days later.

While you're in the General tab, check the Audio messages setting too. By default recorded audio clips expire two minutes after you listen to them; if it's been switched to Never, years of voice messages may be sitting in your history alongside everything else.

Read this before you switch: it deletes immediately, and it syncs

Two things catch people out:

• The cleanup is not gradual. The moment you confirm, everything older than the chosen period is deleted — not just new messages going forward.
• With Messages in iCloud on, deletion syncs everywhere. If you've enabled Messages in iCloud (in Messages → Settings → iMessage), your history is one shared database — a conversation deleted by this setting disappears from your iPhone and iPad too. If Messages in iCloud is off, each device keeps its own copy and only the Mac is cleaned up.

Before you confirm, save anything you actually need: screenshot the important threads, or drag photos and files out of a conversation into a folder. There is no undo and no Trash for deleted messages.

Check how much space you're getting back

Your entire local Messages history lives in ~/Library/Messages, with attachments as the usual heavyweight. Measure it before and after:

# See how big your Messages history is on disk (read-only, changes nothing)
du -sh ~/Library/Messages
du -sh ~/Library/Messages/Attachments

You can also open System Settings → General → Storage and find Messages in the app list. Multi-gigabyte totals are common; group chats full of videos are almost always the reason.

One note on what you're measuring: if Messages in iCloud is on, part of your history may already live in iCloud rather than on the Mac, so the on-disk number understates the total. The retention setting still helps on both fronts — deleted conversations stop counting against your iCloud storage as well as your disk. Give macOS a few minutes after the cleanup before re-checking; freed space doesn't always show up instantly.

Changing your mind

The setting itself is fully reversible: set Keep messages back to Forever and Messages stops deleting anything from that point on. What it can't do is resurrect history that's already gone. The one exception: if Messages in iCloud was off, an iPhone that still holds the old conversations keeps them independently.

If you'd rather keep messages but lose the bulk

Most of the space is attachments, not text. If deleting whole conversations feels too drastic, you can clear Messages storage selectively — remove the videos and GIFs while the words stay put.