This post explains how to solve an issue where installing the Azure Backup Server or DPM agent to a machine fails with a 0x80990a2b error.
I was asked to deploy Azure Backup to backup content on PCs in the office (organized admins –> that’s another story). I decided to test with my Windows 10 PC. I logged onto our Azure Backup server, and used the GUI to deploy the agent and it failed:
Install protection agent on <Machine Name> failed:
Error 347: An error occurred when the agent operation attempted to create the DPM Agent Coordinator service on <Machine Name>.
Error details: Unknown error (0x80990a2b)
Recommended action: Verify that the Agent Coordinator service on <Machine Name> is responding, if it is present. Review the error details, take the appropriate action, and then retry the agent operation.
I searched my services for something called DPM Agent Coordinator and found nothing. The DPM community is full of stories about Windows Firewall causing issues – I tried to disable it but it made no difference. And the 0x80990a2b error wasn’t appearing in my search results.
Next I decided to try a manual installation on my PC. That failed with the same error, but this time there was a clue:
There is a log file for the installation. I opened the log and started reading. There was the error about not being able to initialize something called an AC (Agent Coordinator). I was getting frustrated but kept reading.
WARNING Failed: Hr: = [0x80990a2b] : MARS agent found. Cannot install Microsoft Azure Backup Agent
Now was exactly when I remembered that I had been backing up my OneDrive using the Azure Backup MARS agent. I remove the agent, cleaned up the backup, and re-ran the original agent deployment from the Azure Backup Server GUI. The agent installed perfectly and was added to the protection group.