Symptoms

Agent registration fails with the following error:

Failed to validate possible tenant change: unintended tenant change

This error usually occurs when re-registering the Agent, e.g. to a different tenant. 

Cause

Issue in the product: resource remains tied to the previous tenant and cannot be registered to a new tenant.

Solution

There are 2 possible workarounds:

• Change MMScurrentMachineID and InstanceID on the affected machine: see How to change MMScurrentMachineID and InstanceID for instructions
• Uninstall Agent on the machine using Cleanup utility, then reinstall it again. 

After applying one of the workarounds, reattempt the registration: see Registering backup client manually