Certain features in SQL Server affect the structure of the database files. When you attach a database to another instance of SQL Server, the file format might not be compatible with a different version of the Database Engine.
For example, this error can be caused by using the vardecimal storage format in a later version of SQL Server and then trying to attach the database files in a version earlier than SQL Server 2005 Service Pack 2.
Determine the version of SQL Server that is running on the originating server. In SQL Server Management Studio, either right-click the server and then click Properties or type SELECT @@VERSION in a query window. Open the database by using the original version of SQL Server. Investigate the features that are enabled on the original database in the instance of SQL Server. Modify these settings to work with the version of SQL Server in which the database will be attached.