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Outlook for Mac: total attachment size exceeds the limit.

The message is too big to send, so Outlook holds it. Here's where it goes, how to stop the error repeating, and how to get the file there another way.

Where the message went

Microsoft says Outlook for Mac keeps a message that’s too large to send in your Drafts folder, not your Outbox. From there you have two choices.

Send it smaller

  1. Open the Drafts folder and select the message.
  2. Remove some of the attachments, then click Send.

Or delete it, and stop the error repeating

Deleting it once isn’t enough. Microsoft says you’ll keep getting the attachment error until you also delete it from the Trash.

  1. Open the Drafts folder, select the message, and click Delete in the toolbar (or right-click it and choose Delete).
  2. Open the Deleted Items (Trash) folder, select the same message, and delete it again.

Still stuck? Microsoft suggests Help > Contact Support in Outlook. Its help also notes that if your Microsoft cloud storage is full, you can’t send or receive email at all.

What is the limit?

Microsoft’s Outlook for Mac page doesn’t give one number. It comes from the email account:

  • Outlook.com: 25 MB for attached files. Microsoft says you can share a OneDrive file instead, up to 2 GB.
  • Gmail: 25 MB for personal accounts, per Google.
  • Work or school accounts: may have their own limit. Ask whoever runs your email.

Can you raise it on your Mac? Microsoft’s help for this error doesn’t offer a setting. Its fix is to send less.

Sources: Microsoft’s My email message doesn’t send (Outlook for Mac) and Sending limits in Outlook.com, checked October 27, 2026.

Other ways to send a big file

For the people you send to every week: Sendoff

Sendoff doesn’t send through Outlook. It’s a Mac app that lives in the notch and sends by Gmail or iMessage. It checks the size before you send: a 48 MB video for someone you usually email goes by iMessage instead, with a note saying why. Drop the file, pick the person, press Send off. It ranks your regulars first, like your accountant or your teammate, and gives you 3 seconds to undo.

Join the waitlist below, and tick the beta box if you want to test it first.