Article ID: 2584294 - View products that this article applies to.
You use one of the following to try to migrate a user's mailbox data from your on-premises messaging environment to Microsoft Office 365:
This issue occurs if the user's mailbox contains one or more messages that exceed the 150-megabyte (MB) message limit.
FailureType : TooManyLargeItemsPermanentException
FailureSide : Target
Message : Error: This mailbox exceeded the maximum number of large items that were specified for this request. --> MapiExceptionMaxSubmissionExceeded: IExchangeFastTransferEx.TransferBuffer failed (hr=0x80004005, ec=1242)
To fix this issue, locate and remove messages that are larger than 150 MB from the user's on-premises mailbox. To do this, follow these steps:
For more info about how to import items into Outlook in Office 365, go to the following Microsoft websites:
If you experience issues when you move mailboxes to Exchange Online in Office 365, you can run the Troubleshoot Office 365 Mailbox Migration
(http://aka.ms/HMTSKB)tool. This diagnostic is an automated troubleshooting tool. If you're experiencing a known issue, you receive a message that states what went wrong. The message includes a link to an article that contains the solution. Currently, the tool is supported only in Internet Explorer.
Still need help? Go to the Office 365 Community
Article ID: 2584294 - Last Review: May 21, 2015 - Revision: 18.0