Tidy MacApple Mail stores a local copy of your messages and attachments in ~/Library/Mail, often 5–50 GB. Don’t delete that folder directly. Shrink it from inside Mail instead: erase deleted items and junk, delete large old messages, and set Download Attachments to Recent or None for big accounts. Copies of opened attachments in Mail Downloads are safe to clear.
- Check the size: du -sh ~/Library/Mail (Terminal needs Full Disk Access).
- In Mail, choose Mailbox › Erase Deleted Items and Mailbox › Erase Junk Mail.
- Find and delete large old messages with attachments.
- In Mail › Settings › Accounts › Account Information, set Download Attachments to Recent or None.
- Clear the Mail Downloads folder of opened attachment copies.
Why Mail gets big
Mail keeps every message it downloads, with attachments, so you can search and read offline. With years of email on several accounts, ~/Library/Mail reaches tens of gigabytes. It's counted in Storage under Mail, and partly in System Data.
Check the size
du -sh ~/Library/MailIf you see "Operation not permitted", give Terminal Full Disk Access in System Settings › Privacy & Security › Full Disk Access. What that is
Step 1: Empty Mail's Trash and Junk
In Mail, choose Mailbox › Erase Deleted Items and Mailbox › Erase Junk Mail, for all accounts.
Step 2: Delete large old messages
Search for messages with attachments, sort the list by Size (View › Sort By › Size), and delete the big ones you don't need. On IMAP accounts this deletes them on the server too, so archive anything you want to keep elsewhere first.
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Step 3: Download fewer attachments
Choose Mail › Settings › Accounts, select an account, and open Account Information. Set Download Attachments to Recent or None. Mail then fetches attachments only when you open them. The messages stay on your mail server.
Step 4: Clear Mail Downloads
Every attachment you open is copied to a separate Mail Downloads folder and kept. Those copies are safe to remove; the originals stay in your email. Mail Downloads folder
Where Tidy Mac fits
Tidy Mac's Clean screen lists the Mail Downloads copies as Safe to clear, and shows how much Mail uses so the numbers add up. It doesn't delete messages; Mail should do that. Pricing
Frequently asked questions
Can I delete the ~/Library/Mail folder?
No. It holds Mail’s local copies and index. Deleting files there can lose messages that aren’t on a server and confuses Mail. Shrink it from inside Mail.
Will removing an account from Mail free space?
Yes, Mail removes that account’s local copies. For IMAP and Exchange accounts the mail stays on the server; for POP accounts it may be the only copy, so export it first.
Why is Mail so big when I barely use it?
Mail downloads every message and, by default, every attachment for each account you add, even ones you never read on this Mac.
Is the Mail Downloads folder safe to delete?
Yes. It only holds copies of attachments you opened. The originals stay in your emails. Details