Since this post, I fount something which better works in an other order :
1/ Keep what you want in the COMMUNITY folder (typically of you use FBW A320)
2/ In the « official » folder, choose a small Osobo folder and suppress it (or just rename it in *.old. Take a folder which is about 10ko)
3/ Start MSFS
4/ Content manager find the missing folder, download it, and start correctly! It seams to repair a config file somewhere…
Hope that will help. Regards. Alain, France