To quickly restore the default settings of your installation of MicroStation V8 XM Edition or V8i, use the

 -restoredefaults command line switch.

In doing so, the following folders will be cleaned:

Deleted C:\Users\user.name\AppData\Local\Bentley\MicroStation\8.11\xxxxxxxxxxxxxxxxxxx
Deleted C:\Users\user.name\AppData\Roaming\Bentley\MicroStation
Deleted C:\ProgramData\Bentley\MicroStation
Deleted C:\Users\user.name\AppData\Local\Temp\Bentley\MicroStation\8.11

Defaults restored. Press any key to exit.

Related Link:
How To Figure Out What The Command Line Switches Are