After having lots of issues getting Assassin's Creed to work last night I got a couple of hours in.
I started playing again this morning and after a while the game crashed. When I went back in I was upto the correct place.
2 or so hours later I decided to take a break, so I went to the menu and quit to Windows. 15 minutes later when I reentered the game I'd lost the past 2 hours of gameplay and the game was back to where it had crashed early. I screamed, yelled and in the end just decided to suck it up and play through again.
I played for just over another 2 and a half hours (getting much further than I had the first time as I had done everything already) only to have the PC crash (I think it may have over heated). Again there was much swearing, this time I didn't want to lose my save data so I backed up the Ubisoft game launcher directory before booting the game, worried that it would resync with my saves from earlier this morning.
When I launch the game it does infact sync with the server and take me back to where I was after the first crash I occured (2-3 hours of gameplay ago, 5-6 hours ago real time as I had played through much of the game twice). I don't want to replay this section of the game a third time! Is there anyway to load my previous save? Or should I just give up and uninstall Assassin's Creed 2
Try playing the game under 'Windows XP SP2 Compatibility Mode', if you are using Vista/7. This has known to somewhat help overcome this AC2 PC save game problem, as also told by this guy out here (InDebt08):
How to Run a Program in Compatibility Mode in Windows 7:
I'm running Windows Vista.
While trying to get my old save back I deleted the one that was stored on the servers, so now I don't actually have any progress, and I can't be bothered playing through the first 5 hours again.
Time to give up I enjoyed the game, but not enough to play through everything again twice (somethings for a third time) with the possibility having to do things a forth or fifth time.
(It's actually quite a good way to make money, they really only need to make half a game then put in so many bugs and drm issues that people just give up).