I've also got a savegame not working. My first five are fine. I suspect the trigger event may have been some sort of research I completed.
Also, a separate thing maybe, I can't seem to see particle rifle or pistol accelarators (the glowy ammo things) when assigning equipment to soldiers. The weapons I see, but not the ammo. I'm not sure if maybe the idea is that you can't reload those during missions? I ended up giving one guy two particle pistols so that he could drop one and use the other if the first ran out of ammunition.