- There are spelling errors in the mapping file. This file maps the PST file in Azure to the correct mailbox in the EXO tenant.
- The mapping file is too large to be validated.
- There are duplicate objects in the EXO tenant. However, they can’t be seen by running commands such as get-mailbox or get-recipient.
- The PST file in Azure is corrupted.
- Check the mapping file to make sure that each mailbox can be seen by running get-mailbox against the Exchange Online environment on all mailboxes that are listed in the file.
- There may be hidden objects in the EXO tenant because the objects haven't been completely removed from Azure. These objects can be found in the Azure Recycle Bin. Remove any users who may conflict with the user whose mailbox is being imported from the Recycle Bin in Azure. To do this, connect to Azure PowerShell, and then run the following command:
Remove-MSOluser -UserPrincipalName <UserUPN> -RemoveFromRecycleBin
- Try to reduce the number of lines in the mapping file to fewer than 50. Or, increase the number of lines to more than 100.
- Try to remove the file from Azure, and then upload the PST file again.
- If the import process has started and shows more than 0% progress, connect to the Exchange Online environment, and then run the following command line:
Get-MailboxImportRequestStatistics (Get-MailboxImportRequest -Mailbox <UPN>).RequestGuid | flThis generates more information about the error that's listed in the failure information.
- If the import process is stuck at 0% or has failed before that point, contact Microsoft Online Services Support by online submission or by telephone .
Article ID: 3164141 - Last Review: May 19, 2016 - Revision: 1