CRM org Update

CRM version update failed, it showing following error:

" if not exists (select * from sysusers where name = '******\CRM2013-ReportingGroup-PR') exec sp_grantdbaccess '******\CRM2013-ReportingGroup-PR' Exception: System.Data.SqlClient.SqlException (0x80131904): The login already has an account under a different user name."