The Veeam Backup Service starts and then immediately stops. Svc.VeeamBackup.log contains errors such as:
<04> Error Unable to acquire privilege 'SeRestorePrivilege'.
According to the Required Permissions page of the user guide, the account used to run the Veeam Backup Service must be a Local System account or must have the Local Administrator permissions on the Veeam Backup server.
These errors occur if you specify a local or domain administrator as the Veeam Backup Service account but set Group Policy such that the account does not have all of the default permissions of a local administrator.
For the two examples above, the permissions are located in Computer Configuration\Policies\Windows Settings\Security Settings\Local Policies\User Rights Assignment
SeRestorePrivilege is “Restore files and directories”
On a domain controller, use Group Policy Management to determine whether these policies have been defined for the OU containing the Veeam Backup server, then check containers with lower precedence (see Group Policy processing and precedence). Alternatively, you can use Group Policy Results or Resultant Set of Policy to identify the problematic GPO. The policy applied to the Veeam Backup server must either be Not Defined or include the user specified as the Veeam Backup Service account.
After changing policy, run gpupdate from a command line on the Veeam Backup server to refresh Group Policy settings, then start the service.