In a VMware environment where you have an Exchange/SQL VM, you need to deploy the Altaro VM tools in order to truncate the logs. If you are noticing the following events being listed in the Windows Security log at the time of the backup, here's how to solve it.
In certain cases the local policy due to restrictions or GPO's the Altaro user is not allowed to log on locally. Upon investigating the details of the event, we notice that the Failure Reason states; "The user has not been granted the requested logon type at this machine."
In order to resolve this issue, open the "Local Security Policy Editor" on the VM and browse to [Local Policies - User Rights Assignment] and then locate the entry [Allow log on locally]
Then add the Altaro user, which was automatically created during the Altaro VM Tools installation. You can find this from the Local Users and Groups on the VM.
If the VM is also running as a Domain Controller, ensure that you add the Altaro user twice. Once under the local machine (machinename\Altaro user) and another as part of the domain (domain\Altaro user).