Error Message:
Cannot open user default database. Login failed.
Login failed for user ‘UserName’. (Microsoft SQL Server, Error: 4064)
The fix for this problem is very simple.
Fix/Workaround/Solution:
First click on Option>> Button of “Connect to Server” Prompt.
Now change the connect to database to any existing database on your server like master or msdb.
Now click on connect and it will successfully log you in. Once you login in the system run following statement for your username and it should fix your problem. Make sure to replace [test] with your username and master with yourdatabase name.
ALTER LOGIN [sa] WITH DEFAULT_DATABASE = master
GO
