On one PC, all my saves got corrupted so I couldn't click on the ground anymore, only on highlightable characters/objects. This made the game unplayable.
Luckily I could continue on my 2nd PC. Until yesterday, when - just before the battles start in Act 3 - I got hit with the 'assertion failed' bug. The saves won't load anymore.
There was a fix posted somewhere on the net for Storm of Zehir - start a new game, copy the .Z file to your previous save - but that doesn't seem to work in the Main Campaign.
Has anyone got an idea how to fix this??? I've sunk well over 50 hours in the main campaign and I don't want to start over, especially if saves get corrupted with a shockingly high frequency.

The .Z thing does work, it's just that you may have to go back a few saves before you find one that's not corrupted. I just started by loading my first save, then my second, etc., until I found the one that broke. For me it was Act I of the OC, and I copied 1200_Highcliff.Z from the good save to my latest save. It started out a little messed up, repeating the dialog that I had completed on my previous save, and some of the background characters didn't seem to behave properly, but I got through it and was able to move on. For example, I was in the "Maiden's Glade", where Elanee's friend was trapped in his big white bear form, but he wouldn't do anything; there was just the "speech bubble" icon when you waved the mouse over the bear, but you couldn't initiate a conversation. Eventually I think Elanee's badger pissed him off enough where he attacked us, and everything worked out as expected from there. This save was several saves after the uncorrupted save, but I think they were consecutive saves in the same session, so that I never would have known when the corruption occurred, because I wasn't reloading the saves each time.

Anyways, hope that helps someone out there. Having a good time tripping down memory lane with this game. (=