It seems that all games depending on UPLAY crash after startup (because UPLAY itself crashes). See screenshot here
Something must be wrong with my Geforce NOW configuration, as this initially worked flawlessly for about a week and then this error occurred. Friends of mine have no issue at all.
Unfortunately I haven't managed to get hold of anyone at Nvidia Support nor is anyone responding to my Geforce NOW Support Forum Request. It seems though that I'm not alone with this problem, as there are similar threads in the support forum.