http://brianseekford.com/index.php/2011/05/17/how-to-fix-sqlerror-filestream-feature-is-disabled/
Essentially you need to follow the steps below:
- Open SQL Configuration Manager and locate your database then right click on it and open up the properties
- Navigate to the FILESTREAM tab and check all the checkboxes then click apply
- Right click on your database again and restart it
- Close SQL Server Management Studio if it was opened then open it up again
- Run the query below
- EXEC sp_configure filestream_access_level, 2
- RECONFIGURE
- Close SQL Server Management Studio and reopen it
- Now you should be able to restore the database!