Is it safe to delete Mail messages and attachments?

The messages, attachments and mailboxes Mail keeps on this Mac for all your email accounts.

Review first

It's your own data, or hard to recreate. Decide item by item.

~/Library/Mail/V*

What it is

Mail stores its copy of your email here, in a folder named for the version of its data format (V10 on current versions of macOS), with a folder for each account and for On My Mac mailboxes. iCloud, IMAP and Exchange accounts keep the originals on the mail server, but mail in POP accounts and On My Mac mailboxes may exist only here. The folder grows with every message and attachment Mail downloads. Mail keeps an index of these files, so change them only in Mail.

If it's removed

Messages you delete in an iCloud, IMAP or Exchange account are also deleted from the server and your other devices. Removing attachments from IMAP messages deletes them from the server too, and they can't be retrieved.

What to do instead

In Mail, delete messages you no longer need, or select a message and choose Message > Remove Attachments. To keep fewer attachments on this Mac, set Download Attachments to Recent or None in Mail > Settings > Accounts > Account Information, or turn on Optimize Storage in System Settings > General > Storage.

FREE

The free analyzer finds it and explains it, with these steps. The app doesn't remove it for you.

Sources

Last checked on 26 Sep 2026. Every entry is written and checked by hand; the app and the command-line tool use the same words.