Hi,
Al is right in what he says, with SMB2 you can't disable oplocking, and it is this that causes the corruption, also make sure disk write caching is disabled.

>We are starting to see more C0000005 errors related to Index Corruption issues than typical. The catch here is that they only occur on Vista only networks. These are solid networks that have run fine for a year or two and since April, 2009 or so, are starting to have more C5 problems.
>
>One particular customer has run our software fine for 2 years with one Vista machine and one XP machine. This customer replaced the XP machine with a Vista machine (so now was Vista only) and within a week got C5 and index errors. This customer put the XP machine back and hasn't had another error. I know that in a Vista->XP network they use SMB... and in a Vista only network, they use SMB2
>
>I'm wondering if somehow a Vista patch hasn't reintroduced a new variant of the old Windows Vista Locking Bug with SMB2:
>http://fox.wikis.com/wc.dll?Wiki~WindowsVistaFileLockingBug~VFP
>
>We have setup dedicated Vista only networks to try and reproduce the bug but can't. At our customers' sites the ICE error only appears after extended use of our software... data entry for 4,5,6+ hours straight on multiple machines. The only routine that modifies the table whose index gets corrupted makes extensive use of BEGIN TRANSACTION.. END TRANSACTION. I have actually simplified this routine to get rid of the nested Transactions but the corruption continues.
>
>Others are seeing this problem too:
>http://social.msdn.microsoft.com/Forums/en/visualfoxprogeneral/thread/8b3d25d5-bda0-4b9b-b24e-d9a3d585a412
>
>This is not a network setup issue. This issue has happened at multiple customers sites repeatedly. It always corrupts the index on the same table. Considering there's not a command in Foxpro called CORRUPT INDEX it shouldn't be code related... but I would certainly entertain any thoughts on code. I really, really think this is Vista related though because this problem NEVER happens with our customers that run only XP machines.
>
>Any ideas?