Before you stop a database, you will want to make sure that there aren't any users currently accessing it. You can do so using the Active Users... function in Model Explorer.
To show all active database users using Model Explorer:
2. In the left navigation pane, expand the SQL icon.
3. Expand the server on which the database is stored.
4. Right-click on the database, then click Active Users....The database users list appears.
You can use this information to inform all users, e.g. by e-mail, that they should close all of their connections to the database before the scheduled shutdown time for the server.