Knowledge Base

Mailboxes are not backed up due to ID mismatch


While running an Exchange backup job in CodeTwo Backup, some mailboxes fail to back up and you receive the following message:

Failed to back up mailbox '<email address>' because its ID doesn’t match the ID of the mailbox existing in the storage. 


This issue occurs only if you have backed up an Office 365 mailbox created shortly after deleting another mailbox that had the same primary SMTP address. You should wait from a few to a dozen of minutes after creating such a mailbox before you attempt to back it up with CodeTwo Backup.

If you already got the said error message, you will not be able to continue backing up such a mailbox. To fix this, follow these steps to delete the mailbox from your backup storage and then back it up again. Once you start your backup job anew or during another backup cycle, in case you have configured a continuous backup job, the mailbox will be backed up without any problems.

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