Azure MARS backup failing - Unable to detect changes in file system

Lodge U.K 6

Hi, I’m having an issue with a file level backup using MARS on a Windows 11 machine. It’s been working absolutely fine, but recently all scheduled backups are failing with “Microsoft Azure Backup Agent is unable detect changes in file system. Ensure MARS backup agent is latest, verify and resolve storage issues that impact backup scratch space and retry operation. 0x07EF8”. There is 80GB free space on the disk and I’ve tried to resync the backup as per this article https://learn.microsoft.com/en-us/answers/questions/842493/initial-backup-failing-on-three-on-prem-vms the agent is the latest as well.

SadiqhAhmed-MSFT 37,921 Reputation points Microsoft Employee

2024-02-07T10:18:20.7766667+00:00
Hello @Lodge U.K Thank you for contacting us on Microsoft Q&A platform.

From the details shared in the post, I see that you had MARS agent installed on Windows 11 machine and it was working fine. However, the scheduled backups started failing.

Based on the error message, it appears to be a scratch folder space issue. As per recommendations: https://learn.microsoft.com/en-us/azure/backup/backup-azure-file-folder-backup-faq#manage-the-backup-cache-folder

The cache folder volumes should have free space that equals at least 5-10% of the total size of backup data.

If the volume has less than 5% free space, either increase the volume size, or move the cache folder to a volume with enough space by following these steps.

If you back up Windows System State, you'll need an additional 30-35 GB of free space in the volume containing the cache folder.

Also, ensure that you are running the latest version of MARS agent - Version 2.0.9266.0

Download the latest version of the Azure Backup agent Source: https://learn.microsoft.com/en-us/azure/backup/upgrade-mars-agent

Hope this helps. Let us know how it goes!

If the response helped, do "Accept Answer" and up-vote it
Lodge U.K 6 Reputation points

2024-02-07T10:29:08.4133333+00:00

Thanks, sorry the actual free space is 113GB 256GB SSD, so there is plently of space. I have installed the current MARS agent as per the various troubleshooting article suggest this, but still the same issue.
Lodge U.K 6 Reputation points

2024-02-07T10:43:48.4333333+00:00

Hi, thanks for the reply. there is 113GB (my 80GB was incorrect) or 256GB, so there is plenty of scratch space. Also as per the other troubleshooting articles the latest version of MARS agent was install but still the same error. Again this has been working fine.
SadiqhAhmed-MSFT 37,921 Reputation points Microsoft Employee

2024-02-07T10:53:03.96+00:00

@Lodge U.K What is the amount of volume being backed up?
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SadiqhAhmed-MSFT 37,921 Reputation points Microsoft Employee

2024-02-07T13:47:32.5533333+00:00

@Lodge U.K Can you confirm that you are running the latest version of MARS agent - Version 2.0.9266.0 ? If yes, let me know, I will try to find possibilities to fix this issue.
Lodge U.K 6 Reputation points

2024-02-08T18:19:29.95+00:00

Yes I can confirm we are running 2.0.9266.0 as I upgraded myself in order to see if it would fix the issue. As I said, I’ve tried adding the registry key to resync but that fails with the same error. many thanks
SadiqhAhmed-MSFT 37,921 Reputation points Microsoft Employee

2024-02-12T12:55:51.5433333+00:00

@Lodge U.K Have you had a chance to see the previous response? If the suggestions were helpful, click “Accept Answer” and Up-Vote. Feel free to reach out to us if you've additional questions in this regard.
SadiqhAhmed-MSFT 37,921 Reputation points Microsoft Employee

2024-02-12T14:21:34.74+00:00

@Lodge U.K We haven't heard back from you. Please reply if you have any questions in this matter and we will gladly continue the discussion.