>This is suck-eggs stuff you've probably already looked at, but have you checked your temp files setting in CONFIG.FPW? And, for each different account/machine you log in as/at, have you checked that the drive mappings are as your VFP app expect? If the tempfiles are going to a local drive, do you have the necessary local permissions to write to that local drive?

Thanks for your ideas, Al, I'm still trying them. For this WS, I have no vfp config tempfile settimgs, and the NT Temp directory appears to be working fine. I will try more permissions changes today, I have a lot of combinations to test, from my two personal accounts to System, Everyone, Authenticated Users, Owner, etc.

>I'd disagree here, what you really need is an expert in NT security/permissions setup first and foremost. You have the knowledge of where you open/write/save files.

Well, NT would be the first priority, but I have solved most of the other NT problems, and, as I say, this problem does not occur using vfp Command window, PRGs, etc, or even smaller EXEs. The more I test, the more aware of exactly where the problem lies:

It appears to be related to the size of the app (very large) and/or number of vfp files open - and quite directly related to multiple large DBCs being open. I also believe every command that ISOs involves either an explicit or implicit vfp index call from a DBC-stored index - either a DBC or table index, in every ISO case. The other errors I occasionally see (cannot update cursor, error reading file) are only after-effects, and not important, I believe.

Several times now the NT machine has actually corrupted either a DCX or CDX, and these are all locally stored indexes. That has got to be significant.