Hi SEE,
I've to admit being stupid - or rather having been blind to the obvious: Because the issue would never arise in RoF, IL-2 or anything else but CloD I assumed the culprit to be CloD or at least the combination of FreeTrack, BlueSoleil, Wii Remote and CloD...
It was only when I started looking at the FreeTrack source code (Pascal..., a long, long time ago

) to maybe find a possibility not to pause the whole FreeTrack, but just to stop transmitting data to the sim. This took me to the FreeTrack forum (where I should have started!, see above

). And - bam! - there it was: The BSOD of pausing FreeTrack (with Wii remote and Bluesoleil) is a
known issue since 2009.
And the solution is, who could have suspected:
just stop transmitting data to the sim instead of pausing FreeTrack. This option is just two inches of scrolling down below the option to pause FreeTrack: In the group "Output" assign a toggle key to "Track-IR". That's it. Just that simple.
And it does have the additional benefit, that blocking the output does not pause FeeTrack and does not stop the Wii remote. Therefore the system does not have to re-discover the LEDs, is therefore faster back and I do not have to set the threshold as low as before (I had the situation that FreeTrack did not rediscover the LEDs after pausing).
Artist