SophosUpdateMgr account in AD gone

Hi,

Our client have failed error on updating status and notice that SophosUpdateMgr account is no longer in our AD? Nobody remove that user account in AD.

Any idea what might have cause it? We uninstalled Sophos Update Manager in one of our dc server and could not reinstalled it again due to user authentication, you think this might have cause the error?

Thanks for those who could give some inputs.