>>
>>If there are some clients with Vista or W7 they might connect via SMB2 which can destroy an index on file server OS > 2003
>
>Did this issue just apply to VFP 9, or also prior versions like VFP 8 and 7?

To all ISAM-file based database tools: Access, dBase, Foxpro, Vfp and others as well. It's an OS bug biting the ISAM.