SQL SERVER 2012 error
You may use t-sql for restore. Make sure that you create new files instead of replacing your existing database.

Try someting like this:

    USE [master]
    RESTORE DATABASE [new database name] FROM  
    DISK = N'path to your full backup' WITH  
    MOVE N'logicaldatafilename' TO N'path to your mdf file',  
    MOVE N'logicallogfilename' TO N'path to your ldf file',  
    NOUNLOAD,  STATS = 5

GO


I hope it helps.
Janos