Borrar listado de servidores y contraseñas sql

SQL Server Management Studio 2014:
C:\Users\%username%\AppData\Roaming\Microsoft\SQL Server Management Studio\12.0\SqlStudio.bin

SQL Server Management Studio 2012:
C:\Users\%username%\AppData\Roaming\Microsoft\SQL Server Management Studio\11.0\SqlStudio.bin

SQL Server Management Studio 2008:
C:\Users\%username%\AppData\Roaming\Microsoft\Microsoft SQL Server\100\Tools\Shell\SqlStudio.bin

SQL Server Management Studio 2005:

• In Windows 8/7/Vista: C:\Users\%username%\AppData\Roaming\Microsoft\Microsoft SQL Server\90\Tools\Shell\mru.dat
• Windows XP: C:\Documents and Settings\%username%\Application Data\Microsoft\Microsoft SQL Server\90\Tools\Shell\mru.dat

fuente: http://www.top-password.com/blog/sql-server-management-studio-saved-password/