I have a "sysdba" login account among the logins in my SQL Server 2014 instance, and I'm not sure why. I can't do anything with it (change the password, user mappings etc) -- I just a get a "user already exists" error, or the changes just don't take.
I've tried looking this up, but all I can find out is that "sysdba" is an Oracle system privilege, not a username. But Oracle isn't installed on this box. So why is it here?