Hopefully, you are saving during the day and saving backups.
Does the issue also strike if you save and close, then open again without restarting Illy in between?
Yes I am saving many times during the day. Every 3 minutes as a rule.
No, I can open and close the applications and files as many times as I wish during the day and everything works just like it should be. I can restart and open over and over again. It just seems to be something that occurs overnight (i know it doesn't make sense but thats whats happening)
Check your time zone.
Where is the CS4 update?
Is Adobe planning to sell us the new CS5 version instead of providing an update?
My time zone is set to Gold Coast, Australia (which is where I am located)
What will changing it do?
I suppose Wade was referring to some more global system settings being awry. Invalid timestamps would crash pretty much any app. This most often happens with wrong dates set on the server, but has known to also affect local files. Check, whether you are not timetravelling in teh future or way back in the past...