I'm not aware of any way in which it can be disabled. I's use a script to scan and empty the clipboard at regular (say a few times a second) intervals.
So it will be impossible to keep it from popping up on the screen? That seems weird. I can understand that the stuff wold be stored, but I should be able to "hide" it so it diesn't keep jumping out at me...??
You've moved the goalposts a little there! What popup? Could you give a little detail of how and when this happens? Perhaps it is related to a single program (Excel?)
Perhaps I overspoke...it's the pane the opens on the right of the Office program, like when you access Help...I am working fine, and suddenly, my screen is 1/3 thinner because of the d..m clipboard pane that has just appeared!