Error when using Microsoft Azure Backup Server with ARM vaults

I’ve done quite a few Azure Backup projects lately, all based on Microsoft Azure Backup Server (MABS) with Azure Resource Manager based vaults – check out this post for more info on Azure Backup.

Recently I got an error when installing Azure Backup Server though. Actually it was when registering with the Recovery Services Vaults, but since it’s part of the installation, the whole thing failed. The error I got was:

Azure Backup Server ARM error

Invalid vault credentials provided. The file is either corrupted or does not have the latest credentials associated with recovery service.

I’ve seen this in other cases, where time was out of sync, but we checked the time over and over again in this case. Made sure time zones was fine and everything. After some time I was sure that this wasn’t a local issue, and reached out to the Azure Backup team. A few messages back and forth, and we found the issue!

The problem is that the Microsoft Azure Recovery Services agent (MARS agent) that comes with MABS is apparently out of date, and is not supported with ARM vaults. A quick fix for that is to download the newest agent from here:

You can check the version of MARS agent by right clicking MARSAgentInstaller.exe in the following location (default): C:Microsoft Azure BackupMARSAgent – and choose Properties, then Details:


In this case, the version number is 2.0.8720.0, and the file is quite old.

Now replace that file (in C:Microsoft Azure BackupMARSAgent) with the MARSAgentInstaller.exe you just downloaded from the link above the screenshot, which is version 2.0.9032.0 (or newer):


Installation now runs through with no issues.

Expect this to be fixed when ARM Recovery Services vaults goes GA, which is hopefully soon.

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