Since a few days, a window pops randomly up (every 30 min or so) and disappears again. It stays in focus for less than a second and it is impossible to read anything.
It could be related to Firefox or not, it is hard to say... Any idea how to catch this?
I have also been having that since the big update last week. Seems that the OfficeBackgroundTaskHandler is the culprit: https://www.ghacks.net/2017/05/30/what-is-that-popup-on-windows-10-that-disappears-after-a-split-second/