This mailbox exceeded the maximum number of large items that were specified for this request

You receive the following error message when you try to move mailboxes to Office 365

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)

This issue occurs if the user’s mailbox contains one or more messages that exceed the 35-megabyte (MB) message limit. Article ID: 2584294

Here is the small script that will help you locate messages that are larger than 35 MB from the user’s on-premises mailbox and export the information to a CSV file.

# Provide path of CSV file that has the list of all EmailAddresses and the list title is “EmailAddress”

$IDs = Import-Csv .\EmailAddresses.csv

IF (!(Test-Path .\LargeItemReport.csv) -eq $false) {Remove-Item .\LargeItemReport.csv}

ForEach ($ID in $IDs) {

Get-MailboxFolderStatistics -Identity $ID.EmailAddress -IncludeAnalysis -FolderScope All | `

Where-Object {($_.TopSubjectSize -Match “MB”) -and ([int](($_.TopSubjectSize).SubString(0,5)) -GE 35.00)} | `

Select-Object @{Name=”Identity”;Expression={($_.Identity.Split(“\”))[0]}}, FolderPath, TopSubject, TopSubjectSize | `

Export-Csv -Path .\LargeItemReport.csv -NoTypeInformation -Append

}

You can also download the script from TechNet Gallery – Click Here

Hope it helps all !!!