SQL Server – Dropped my default database

Today I learned an important lesson about Sql Server 2005, don’t change your default database unless you absolutely have to.  I set mine to DatabaseX and then I promptly dropped DatabaseX.  When I tried to log in I got a nice error message

            Cannot Open User Default Database, Login Failed

I didn’t setup the VM that I was using, so I didn’t know the SA password.  I basically had no way to get back into the server.  So if you ever find yourself in this predicament, execute the following from the command line:

C:\> sqlcmd -E -d master 
1> ALTER LOGIN [YOUR USER NAME HERE] WITH DEFAULT_DATABASE=master 
2> GO
 

That will reset your default database back to master and you can login again.