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cjm1903
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Veeam backed up DC boots into Active Directory repair mode

Post by cjm1903 » Jul 22, 2016 1:59 pm

Hello all,

We have a virtual domain controller (Windows Server 2012) that is backed up by Veeam every evening. Occasionally we see the error "ErrorL VSSControl: Failed to prepare guest for freeze", and the only solution to this is to reboot the domain controller and run the backup again - after which the backup of the domain controller completes successfully.

When rebooting the domain controller we have to be careful to check the boot options in msconfig, because we often find that the Server is set to Safe boot in Active Directory repair mode. Unchecking Safe boot and changing the startup selection from selective startup to normal startup does not remove the safe boot option and we have to run bcdedit /deletevalue safeboot to remove the flag. Once this is done we can safely reboot the Server and it boots up as normal.

We can't figure out however why it occasionally does this, and we are wondering if it is something to do with the Veeam backup. I realise that the Server will boot into DSRM mode if a restore is performed, however we have not performed a restore of the domain controller and indeed never have to date, so I'm unsure why this keeps happening. It doesn't appear to happen after every reboot, but something is clearly putting into DSRM mode.

Any ideas?

Thanks,
Craig

foggy
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Re: Veeam backed up DC boots into Active Directory repair mo

Post by foggy » Jul 22, 2016 2:54 pm

Craig, I don't think this is Veeam B&R-related, however, you can contact technical support to investigate occasional VSSControl issues, probably they have similar nature.

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Re: Veeam backed up DC boots into Active Directory repair mo

Post by pbaideme » Mar 04, 2017 5:02 pm

Craig, we are experiencing the same issue, with the safe boot Active Directory Repair Mode being randomly checked, after being backed up by Veeam. Did you ever find a solution to this issue?

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Re: Veeam backed up DC boots into Active Directory repair mo

Post by foggy » Mar 06, 2017 12:10 pm

Do you see similar errors during backups prior to that?

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Re: Veeam backed up DC boots into Active Directory repair mo

Post by pbaideme » Mar 06, 2017 1:15 pm

No, We started to notice this randomly when the DC's do their weekly reboots, after we installed Veeam Endpoint Backup ver 1.5.0.306. This has only happened on our physical DC's (2008 R2) so far. This seems to be very sporadic, 1 or 2 times per DC over the past 3 months since we have bee using the VEB. The VM DC's being backed up via Veeam have been fine. We have had 3 different Windows engineer searching the Windows logs but have found nothing yet.

foggy
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Re: Veeam backed up DC boots into Active Directory repair mo

Post by foggy » Mar 06, 2017 4:41 pm

Veeam B&R indeed enables DSRM inside DC's guest OS during backup, but disables it back after the backup. There was an issue on MS side that might result in DSRM not being disabled that was worked around in the latest version of Veeam B&R. I'm not sure about Endpoint though. You can contact support for a closer look.

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Re: Veeam backed up DC boots into Active Directory repair mo

Post by StephenWagner7 » Apr 29, 2018 4:05 pm 1 person likes this post

foggy wrote:Veeam B&R indeed enables DSRM inside DC's guest OS during backup, but disables it back after the backup. There was an issue on MS side that might result in DSRM not being disabled that was worked around in the latest version of Veeam B&R. I'm not sure about Endpoint though. You can contact support for a closer look.
Thank you for this info!

I'm having the same issues as the posters above. No issues until I loaded up Veeam trial and this occured on one of my Server 2016 "Server Core" DCs. Didn't even realize what was going on for hours. Took it out of DSRepair, but it's nice to see this explanation as it can now put my mind at ease! :)

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