See if http://www.berezniker.com/content/pages/visual-foxpro/lowering-memory-usage-application may help.

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>I'm trying to understand how to optimize an VFP application. I have a program that appends approximately 250k records into a free table, does some basic processing and then writes the records out to a flat file via the "copy to sdf" command, closes the table then another series of programs run all within the same instance of VFP.
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>When I watch the VFP6.EXE via the Task Manager and the program I describe above runs, it's memory usage climbs to the max that I've set with the sys(3050) command, which is about 512MB. The problem I see is that the memory never releases even when the table closes and that particular program closes. I've tried to use the FLUSH and sys(1104) commands but those don't seem to make any difference.
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>I cannot close the VFP instance nor can I use the CLOSE ALL or CLEAR ALL commands. Anyone have any ideas or is this just an issue with VFP6?