>So here is the simple-minded solution (as we discussed by phone).
>
>I used Total Commander to change the modified date of the Include file. I moved it back a day. After that the Build settled down to 2.5 seconds. I didn't test backdating by an hour or a minute.
>
>Still a mystery to me why this works, or alternatively, why the Build does not get faster automatically a day later when the Include file is a day old. Yet what I have been seeing is that once the Build gets stuck on slow it would stay that way for days or weeks.

And I've checked on my side and still have the weird recompile of the same twelve class libraries every time I build. I still haven't found the time to check whether these are the one with .h files or the ones with active X controls in them, or is there something else.

The .h file dependency may be checked in a simpler manner, by just adding a few hundred to their records in the pjx file.

Still inconclusive, but it seems that I'm having a recompile on any class library containing an olebound control for an activeX that isn't properly installed on my machine (I thought I have reinstalled everything, but apparently I didn't).