How can I change my default database in SQL Server without using MS SQL Server Management Studio?

What you can do is set your default database using the sp_defaultdb system stored procedure. Log in as you have done and then click the New Query button. After that simply run the sp_defaultdb command as follows:

Exec sp_defaultdb @loginame='login', @defdb='master' 

To do it the GUI way, you need to go edit your login. One of its properties is the default database used for that login. You can find the list of logins under the Logins node under the Security node. Then select your login and right-click and pick Properties. Change the default database and your life will be better!

Note that someone with sysadmin privs needs to be able to login to do this or to run the query from the previous post.

Thanks to this post, I found an easier answer:

1. Open Sql Server Management Studio

2. Go to object Explorer -> Security -> Logins

3. Right click on the login and select properties

4. And in the properties window change the default database and click OK.