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Hi Everybody,

a Customer of mine posted the following in R&D forum because we have some issues with his M365 Backup. They have a Case open since May adressing this issue but there is only litte to none progress. I thought that maybe anybody here might had a similar issue in the past and maby even a solution or workaround:

We’re currently facing a critical issue involving both Veeam Backup for Microsoft 365 and Veeam Backup & Replication (VBR), and we’re hoping to hear from others who may have encountered something similar.

Background: After restoring Office files (Word, Excel, PowerPoint) — whether from Veeam Backup for Microsoft 365 or via VBR from local backups — the files can no longer be opened. They appear to be corrupted, even though they were fully functional in their original state on SharePoint or in the file system. Restoring to different SharePoint sites or local paths didn’t help. One notable detail: the restored files are smaller in size than the originals.

Suspected Cause: We suspect a connection to Microsoft’s Sensitivity Labels (specifically the “Confidential” label). The affected files were labeled accordingly, and our internal documentation states that only pre-authorized users are permitted to open or edit them.

Questions for the Community:

Has anyone experienced similar issues with corrupted files after restoring from Veeam Backup (M365 or VBR)?
Was there any link to Microsoft Sensitivity Labels or Conditional Access policies?
Were you able to resolve the issue through configuration changes or workarounds?
Are you using Microsoft’s “Confidential” sensitivity label in production alongside Veeam Backup — and if so, what has your experience been?
Context: Veeam Support is involved (Case #07706842), but no final resolution has been provided yet. They’ve confirmed that Conditional Access applies at the site level, not the file level — but there still seems to be a conflict in our case.

We’d really appreciate any insights or shared experiences — especially if you’ve successfully integrated Microsoft Sensitivity Labels into your backup and restore strategy.

 

Link to R&D entry: Corrupted Files After Restore from Veeam Backup for M365 and VBR – Related to Microsoft Sensitivity Labels? - #07706842

 

Thanks for you help!!

Regards

Chalid

​@CMF The team is working on this to get it resolved, but I am not sure about a timeline at this point in time

Hi ​@Mike Resseler , 

i´m aware of that and the post was not supposed to disparage the Support in any way. I was just hoping that someone here might have had similiar issues before and maybe even fiigured out a workaround by them selfs. 

Ah sorry, no, there is no workaround I'm afraid. There is a small size of bites that are missed (it is a bit more technical but...) and without those we cannot restore decently

Ok. Thanks for the clarification. But is this a common issue when using the “Confidential” label as described or is this something unique to this specific environment? 

Interesting behavior. I’ve not experienced this personally in our environment Chalid, but we don’t have Sensitivity Lables or Conditional Access options enabled for Office docs..at least none that I’m aware of. Thanks for sharing this ‘bug’.

Interesting. I have no expierience and cases about this behavior, but it is a good thing to know.

Thanks for share you trouble ​@CMF 

Hi. We still don´t know if this is a “bug” or just an isolated issue in this particluar environment. So lets wait what support finds out. 

According to Mike (Veeam Product Manager), it does appear to be a bug they’re aware of and are working to resolve ​@CMF . I would suspect a patch will be released in the “near future” to address it; altho..as Mike stated...no timeline as of yet.

Sorry all, I am on vacation. It seems to be a bug indeed. I believe a KB will be posted once all is fully clear, and a fix is already in the works

No worries Mike. Thank you for the clarification. Enjoy your vacay! 😎🌴

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