Those are different versions of SQL Server ODBC driver:

1. 'DRIVER=SQL Server' - the SQL Server ODBC driver for SQL 2000 (or earlier)
   
2. 'Driver=SQL Native Client' - the SQL Server ODBC driver for SQL 2005
   
3. 'Driver=SQL Server Native Client 10.0' - the SQL Server ODBC driver for SQL 2008
   

The earlier versions of ODBC driver doesn't support features introduced in later versions of SQL Server. On other hand VFP is not fully compatible with SQL Server ODBC driver for SQL 2005 and later (varchar(max), etc.)
You can use CursorAdapter with DataSourceType=ADO and latest SQL Server Native Client to utilize all the features of SQL Server.



>
>May I know the difference between the following options for connection string
>
>lnConn =SQLSTRINGCONNECT('DRIVER=SQL Server;DATABASE= ....
>
>versus
>
>lnConn =SQLSTRINGCONNECT('DRIVER=SQL Native Client;DATABASE= ....
>
>I have problems using the 1st one with DB Encryption.
>
>Switching to the 2nd version solves the DB encryption problem but the second version cannot recognize the newer data types such as varchar(max) in SQL2005
>
>Your advice much appreciated.
>
>Thanks & Best Regards