>But I don't have any "scheduled tasks" and the FindFast thingy is set to go every 999 hours.

I have Windows XP but haven't bothered to install it yet. Check your Control Panel; there may be a "Scheduled Tasks" Icon there.

I would also check under "Services". (Probably) This stuff would be flagged as "running" with an "Automatic" startup. You could "stop" these tasks and change their start-up to "Manual".

(I'm extrapolating here based on what goes on in Win98 and W2K).

If that doesn't help, I would try to narrow things down by doing a file/folder or Registry search on "defrag". That will usually provide additional context information (eg. "Startup" programs/folders).

>
>In addition, the .DBFs are by far the largest of the files involved. They remain untouched while the .FPTs (most fragmented) and the CDXs were! How to explain that???

I expected that "auto defraging" is partially related to the "last used" date of a given file. Also, everytime you "touch" your system, all "auto activities" will be terminated. The odds that a "large" file in the process of being "auto defragmented" will conclude before you touch the system will be smaller than for a smaller file; hence, Windows may consider smaller files first based on the amount of perceived quiet time available.

>PS I tried to replicate the behaviour on my Win2000 Pro notebook and it doesn't seem to happen there?!?!?!?

I imagine that "XP Home" caters more to us "dummies" than Win2000 Pro does.

As I mentioned, this "auto housekeeping" seems to have originated in Win98, the "non-Pro" OS.