SQL Server Management Studio 2012 Error 948

Hello
I get the following error when trying to attach a database:
TITLE: Microsoft SQL Server Management Studio ------------------------------ Attach database failed for Server 'WLKCNU11216XJ\SQLEXPRESS'.  (Microsoft.SqlServer.Smo) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=11.0.2100.60+((SQL11_RTM).120210-1917+)&EvtSrc=Microsoft.SqlServer.Management.Smo.ExceptionTemplates.FailedOperationExceptionText&EvtID=Attach+database+Server&LinkId=20476 ------------------------------ ADDITIONAL INFORMATION: An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo) ------------------------------ The database 'C:\PROGRAM FILES\MICROSOFT SQL SERVER\MSSQL10_50.SQLEXPRESS\MSSQL\DATA\ADVENTUREWORKS2012_DATA.MDF' cannot be opened because it is version 706. Th ...