Robert,

>On one machine (only one!, it's a Windows 2000) one tempfile is nearly 2 GB in size.
>Due to this huge tempfile the application hangs.
>
>As mentioned before this is can only be monitored on this one machine.
>
>Did anybody ever come over such a strange behaviour before or know how to fix it?

Are you sure the temp file belongs to VFP? When the app crashes I assume the temp file doesn't clear out. Have you tried deleting it?

Is it possible that that use has run some code that has a SQL statement that is doing something like a cartesian product?