To set a database to Multi-user mode:
1. In Object Explorer, connect to an instance of the SQL Server Database Engine, and then expand that instance.
2. Right-click the database to change, and then click Properties.
3. In the Database Properties dialog box, click the Options page.
4. From the Restrict Access option, select Multi user
5. If other users are connected to the database, an Open Connections message will appear. To change the property and close all other connections, click Yes.
If SQL Express is installed, install the SQL Studio Management Server for the version of SQL Express. Use add remove programs to check what version of SQL Express is installed.