Additional SqlServer database error

method one

1. .Mdf file you want to add a database, right click and select Properties
2. Click Security Properties page, select Authenticated Users, click Edit
3. Authenticated Users Full Control permission is selected, click OK, OK click Properties interface
4. Similarly, .ldf file, right-click on the database, open the properties. According to the above steps can be set up again

Method Two

Open the installation directory of the database instance, open the DATA folder.
(Such as my address for the instance directory: D: \ Microsoft SQL Server \ MSSQL10.MSSQLSERVER \ MSSQL \ DATA may then install fashion in the C drive)
to be attached database. mdf and file. ldf file, cut or copy to the DATA folder
completing the above steps, re-attach the database