we should probably make this fix a sticky.
I built a new system over the summer. I reinstalled SH5 over the weekend from the original CD. All went well, the program logged on and updated to v 1.2. I was able to log on to Uplay. However, when I went to start the game, I kept getting the message that "Uplay has ceased working".
As suggested, I uninstalled the Ubisoft Game launcher, reinstalled that latest version and problem solved, game works fine.
Now I just have to catch up on the latest mods.