Thank you for the suggestion !
Unfortunatly , it didn’t work.
I did clean the pageFile by changing the RegEdit entry, rebooted and …
After a first completed flight, I had a CTD after 5 minutes during the second one.
It was a 0xc0000374 on ntdll.dll
(All online services were ON)
THX, it has worked for me perfectly, no problems so far. Do I have to set the memory mgmt back to 0?
Glad to hear that Aton. Set it back to zero indeed to switch it off again.
wilco
and thx again!
Thanks for the advice but alas it’s not helped the ctd’s for me. As long as I don’t move the plane from parking then all is good 
Seems to me that the issue is location-based. Seems to me that I can fly anywhere in the UK without any crashes. I’ve done a bunch of flights from EGSS to EGPH with no crashes + GSX and custom scenery for both airports.
However, I’ve tried loading a flight at EDDK a few times and my sim would crash to CDT every single one of them. I had the same problem at LPPR as well (all online services turned onexcept for traffic).
I installed the latest NVIDIA driver and was able to start FS 
My theory is that msfs2020 doesn’t do RAM management well.
and if your RAM is a bit overclocked, or even if is set to the maximum frequency supported by the BIOS, the CTD comes!!.., even if the other games and memory stress tests don’t fail.
(sorry my english)
Hmm, peeking and poking: do I detect an old time Basic programmer?