Abnormal Increase in Exchange incremental Data Processed By Veeam Backup for Microsoft 365

Issue Summary

Some customers using Veeam Backup for Microsoft 365 to back up Microsoft 365 exchange data may have experienced an unexpected increase in the amount of data being backed up between August 7 and August 21, 2023.  Microsoft has confirmed Microsoft has confirmed this issue in the message EX6700041, which will be displayed in the Microsoft 365 Admin Center of some organizations with affected mailboxes.that this was related to a limited incident that caused some Microsoft Exchange Online environments to have older emails unexpectedly resurface, resulting in an increase in email data in some Exchange Online mailboxes. Those emails that were changed causing them to resurface unexpectedly, must be captured by Veeam Backup for Microsoft 365 to ensure backup continuity. Although those emails may have been backed up previously, their current state is different than it was, so they must be backed up. There is no way to reclaim the space utilized by the backup of these resurfaced emails, as it is technically changed data.

This situation is discussed in further detail in Veeam's RND forums.

Advised Actions

• Check the reports and monitoring activity from after August 7th to determine if your setup is affected by this issue.
• Any impacted Veeam Backup for Microsoft 365 jobs must be allowed to be completed.
• If you have opened a Microsoft Support Case on behalf of your contract and would like more Veeam details regarding the issue to help address it with Microsoft, or should you have any questions, please don’t hesitate to contact Veeam Customer Support.

As the issue causing the unexpected changes has been identified, and no further changes will occur, this issue is now considered resolved.
This Veeam KB article will be auto-archived on 2023-12-07.