I fought the same issue for several days and finally traced it to a single bush trip in the Italy world update. When this bush trip was installed using Content Manager, the sim would CTD and then crash again during the load screens when restarting (unless in safe mode).
After figuring this out I was able to install the full Italy update with the exception of the one bush trip and now everything is working. Hopefully you can do something similar with the Nordic update.
The bush trip in question was one that I had almost fully completed, but when I opted out of the SU11 beta (ultimately by full re-install) I lost all progress. To complete the bush trip, I used the teleport feature in developer mode to rapidly re-fly all the legs I had already completed. After that, it showed that I had 100% completion for the bush trip but apparently when installing SU11 there was a conflict. Not sure how to fix this, but happy at this point that everthing else seems to be working.