If you get this message when you try access to you database manager, could be because you default database is down or missing. To fix this I made this:
- In dialog “Connect to server”, click in Options
- In Connections Properties Tab, in the field “Connect to Database” you must write some database, like “master” or other that is active. Note: Don’t select “<Browse server> because this will raise the same error “Cannot open user default database, login fails”
- and execute (Change MACHINE\USER to match with your user account): “ALTER LOGIN [MACHINE\user]
WITH DEFAULT_DATABASE = master
ps: SQLCMD is not necessary :)
Thank to post of benjamin harrell and comment of Fritz Laurel.