Troubleshooting Exceptions: System.Data.SqlServerCe.SqlCeInvalidDatabaseFormatException
A System.Data.SqlServerCe.SqlCeInvalidDatabaseFormatException exception occurs when SQL Server Compact 3.5 opens a database file that was created in an earlier version of the product.
Remarks
You can update the database file by using Visual Studio 2008 or by using the API System.Data.SqlServerCe.SqlCeEngine.Upgrade.
For more information, see SQL Server Compact 3.5 Class Library.