If you are not getting the root password prompt when you try to start MCC, you can fix the trouble by editing the main menu.
ALT+Click the menu button, then select
menu editor in the pop up list of options.
Navigate to
System > Configuration > Configure your computer in the menu tree (left).
The
command: text entry field (right pane) should contain:
If it does, then something else is going on.
Check mark
Run as different user: in the right pane.
In the
Username: text entry field enter:
To save your changes, open the
File menu and select
Save.
HTH,