Azure MARS agent failing (CRC Error but chkdsk is error free)

Question

Azure MARS agent failing (CRC Error but chkdsk is error free)

Andrew Howard 1

We use the MARS agent to backup on prem to an azure vault.
One of the newly installed server will not even complete the initial backup.
It fails with an error: The operation failed because of a protection agent failure. Data error (cyclic redundancy check) (0x80070017)

The log itself is full of entries similar to:

-FSWrapper.cpp WARNING Hr: = [0xce3d9100] Unable to CreateFile \?\Volume....error :5
-FsUtils.cpp WARNING Not able to obtain FileId for (\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy66\

Last completed state for Ds Id (8566497403364998392) is 18

An initial chkdsk showed problems to a /f was run followed by a reboot.
Same problem occurs.

Does anyone have any suggestions please?
This server is set up the same as our others ans has the same AV policy exclusions appled (Sophos Endpoint).
Has the latest MARS agent,
I have tried uninstalling the backup software. I have manually removed all the installation & scratch folders.
I have reinstalled using another vault.
chkdsk still shows as OK on all volumes.

SadiqhAhmed-MSFT 49,331 Reputation points Microsoft Employee Moderator

2022-05-30T16:44:33.467+00:00
Hi @Andrew Howard - Thank you for your post!

From the details you shared, I understand that you have installed MARS agent on a new server and its failing initial backup. I see that you have already tried few troubleshooting steps that did not yield expected results.

Just wanted to ensure you followed below steps to change the scratch folder location:

To stop the CBEngine, In elevated command prompt run the command:
Net stop obengine

Copy the scratch folder to a different drive with enough space (Suggest to copy instead of move; the original can be removed after confirming that everything works)

Update following registry entries with the new path to scratch folder:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Azure Backup\Config]
ScratchLocation
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Azure Backup\Config\CloudBackupProvider]
ScratchLocation

Net start obengine

Also, make sure you followed this guide - https://github.com/MicrosoftDocs/azure-docs/blob/main/articles/backup/backup-azure-manage-mars.md to add AV exclusions.

If you are sure, you have already tried these steps, then I would recommend contacting Azure technical support team by raising a technical support request for further investigation.

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SadiqhAhmed-MSFT 49,331 Reputation points Microsoft Employee Moderator

2022-05-30T16:44:33.467+00:00

Hi @Andrew Howard - Thank you for your post!

From the details you shared, I understand that you have installed MARS agent on a new server and its failing initial backup. I see that you have already tried few troubleshooting steps that did not yield expected results.

Just wanted to ensure you followed below steps to change the scratch folder location:

To stop the CBEngine, In elevated command prompt run the command:
Net stop obengine

Copy the scratch folder to a different drive with enough space (Suggest to copy instead of move; the original can be removed after confirming that everything works)

Update following registry entries with the new path to scratch folder:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Azure Backup\Config]
ScratchLocation
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Azure Backup\Config\CloudBackupProvider]
ScratchLocation

Net start obengine

Also, make sure you followed this guide - https://github.com/MicrosoftDocs/azure-docs/blob/main/articles/backup/backup-azure-manage-mars.md to add AV exclusions.

If you are sure, you have already tried these steps, then I would recommend contacting Azure technical support team by raising a technical support request for further investigation.

Answer 1

Andy White 0

I'm getting the same issue after having not issues at all, I'm not sure what's kicked this off, unless it's the latest agent.

Did you find a fix in the end at all?

Thanks.

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Azure MARS agent failing (CRC Error but chkdsk is error free)

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