Mail taking up space on Mac, and how to clear it.
Apple Mail keeps a copy of your messages and their attachments on the Mac, for every account, for years. Here's where that lives and how to shrink it without losing mail.
The short version
Mail keeps messages in ~/Library/Mail and attachments you've opened in Mail Downloads. To clear Mail storage, set Download Attachments to Recent or None in Mail › Settings › Accounts, delete large messages you don't need and erase deleted items, and remove accounts you no longer use. Don't delete files in the Mail folder by hand.
Why Mail takes up so much space on Mac
Mail downloads your messages so you can read them offline and search them fast. With an IMAP account like iCloud, Gmail, or Outlook, the mail also stays on the server, so the Mac's copy is a convenience, not the only one. With years of mail and attachments across several accounts, it adds up to gigabytes.
| What | Default location | On one Mac |
|---|---|---|
| Messages and attachments | ~/Library/Mail | Guarded by macOS; measure it in Storage settings |
| Attachments you've opened | ~/Library/Containers/com.apple.mail/Data/Library/Mail Downloads | Copies, safe to clear |
macOS guards both folders: on the Mac this page was written on, Terminal got “Operation not permitted” trying to read them. Check Mail's size in System Settings › General › Storage.
How to clear Mail storage on Mac
Download fewer attachments
- Open Mail settings. In Mail, choose Mail › Settings, then click Accounts.
- Pick an account. Select it, then click Account Information.
- Change Download Attachments. Choose Recent or None instead of All. Attachments download when you open them.
Delete large messages
In a mailbox, choose View › Sort By › Size to put the biggest messages at the top. Delete the ones you don't need, then choose Mailbox › Erase Deleted Items so they're gone from the Mac too.
Clear Mail Downloads
When you open an attachment, Mail saves a copy in Mail Downloads. The originals stay in the messages, so these copies are safe to remove. In Finder, choose Go › Go to Folder, paste ~/Library/Containers/com.apple.mail/Data/Library/Mail Downloads, and move what's inside to the Trash.
Remove accounts you don't use
An old work account can be most of Mail's space. Remove it in System Settings › Internet Accounts, or turn off Mail for it there. With IMAP, the mail stays on the server.
Is it safe to delete the Mail folder?
No. Mail keeps an index of every message in ~/Library/Mail. Delete files there by hand and Mail can lose track of messages or rebuild for a long time. For POP accounts, the Mac's copy may be the only one. Use the steps above instead. For other folders that grow on their own, see Messages, Photos, and everything else taking up space.
Disk Forecast and Mail
Disk Forecast won't delete mail: Mail keeps track of every message. Without Full Disk Access, it skips ~/Library/Mail entirely, so it never sets off a permission prompt. With Full Disk Access, it measures the folder, and if Mail is one of your biggest, it shows under Taking the most space in the menu. It's free.
Questions
Why is Mail taking up so much storage on my Mac?
Mail keeps a local copy of every message and, by default, every attachment, for every account. Years of mail across several accounts can reach many gigabytes.
How do I reduce Mail storage on a Mac?
In Mail › Settings › Accounts › Account Information, set Download Attachments to Recent or None. Then delete large messages, erase deleted items, clear Mail Downloads, and remove accounts you don't use.
Where does Apple Mail store attachments?
Inside ~/Library/Mail with the messages. Attachments you've opened are also copied to Mail Downloads, in ~/Library/Containers/com.apple.mail/Data/Library/Mail Downloads.
Can I delete the Mail Downloads folder?
You can delete the files in it. They're copies of attachments you opened, and the originals stay in the messages.
If I remove a mail account from my Mac, do I lose my email?
Not with IMAP accounts like iCloud, Gmail, or Outlook: the mail stays on the server, and only the Mac's copy goes. With a POP account, the Mac may hold the only copy, so back it up first.
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