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Change Email attachment size limit Outlook 365 for MAC pop3 or imap

WEA 0 Reputation points
2026-03-05T18:17:57.19+00:00

My ISP has no size limit for e-mail attachments and the arbitrary 20mb limit imposed by Microsoft is more than a little frustrating for both me and my clients.

Is there a way to raise this limit?

Office 365 or MAC

Classic/Legacy Outlook (Because New Outlook wasn't saving messages to the local drive.)

Please advise.

Microsoft 365 and Office | Other

2 answers

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  1. Bob Jones AKA CyberTaz MVP 434.8K Reputation points
    2026-03-06T18:16:18.06+00:00

    If compressing the file to be attached isn't sufficient I suggest using Help> Feedback in the New Outlook menu bar to submit a feature request to the development group, This is something which needs to be addressed at the programming level.

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  2. Bob Jones AKA CyberTaz MVP 434.8K Reputation points
    2026-03-06T02:37:33.5533333+00:00

    My understanding is that this is not a matter of discrimination against Mac users. The increase can be made in one of 2 ways:

    • Admin action in an Exchange/business server environment.I believe Mac clients should have the same benefit
    • Local increase by way of a Registry hack, but there is no registry access supported by macOS

    Either way, the sender's service may have no limit but the service of virtually all recipients is restricted — although informal, 20mb is a rather universal standard. An oversize attachment may send OK but still will result in a bounce-back or be stripped.

    Have you considered the recommended method of saving to a cloud & including a share in in the email message?


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