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Ral EdmundsFlag for Australia

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Outlook for Mac. Messages too large. Mime Issue

Hi all,

I have a client who is using outlook for mac to connect to exchange. We are experiencing a couple of issues that i think may be related.

1. Outlook is constantly using huge amounts of data.
2. Outlook is constantly generating sync issues indicating that a message was too big to sync to exchange.
3. Some emails are being modified/corrupted along the lines of
"This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible."

Troubleshooting completed
1. I have identified approximately 32 messages within outlook that are over the Exchange 50MB limit.
2. Almost all of these messages contain the MIME error and a huge amount of apparently random code in the body (I am guessing a representation of the attachments)
3. At least in some cases (have not checked many) if I search for the same email in webmail on the exchange server, I can find it and it does not have the MIME error.
4. If I search for the message on the client, I can find multiple copies. 1 Seems to be OK and intact without the MIME error and multiple copies of the message with the MIME error.

Background
This client was recently migrated from a local IMAP server to the exchange server. After some issues with the 'automated migration'  I manually migrated most users including this Mac user. This involved, on a PC, connected to IMAP server. Downloaded all emails. Exported mailbox to PST. Created new profile. Connected to exchange server. Then imported PST and allowed to sync from PC to Exchange. Then created account on Mac.

Based on this I am confident that there cannot be emails larger than 50MB on the Outlook for Mac as all email has been delivered from the Exchange Server.

What appears to be happening, in my very basic understanding, The user sends an email, It successfully goes out through exchange. As part of the sync or acknowledgement back to Outlook, outlook is identifying a MIME incompatibility, It creates a duplicate message with the MIME warning and a whole lot of Text content. This then makes the message >50MB and the message wont sync backl to exchange. But it keeps trying to sync these message leading to constant maxing out of the upload bandwidth.

Does anyone know the cause and resolution to these MIME errors? Is this likely to be creating the issue that I have described?
Avatar of Edward van Biljon (MVP)
Edward van Biljon (MVP)
Flag of United States of America image

Hi

Is this client running the latest Office for Mac with all its updates or a legacy version?
Avatar of Ral Edmunds

ASKER

The latest version.
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