Disclaimer: I have not updated yet and will not update until a hotfix is released because I play on long lifespan... even though I REALLY WANT some of the things in the update...
I agree with Slytherclaw72. Roll back to a previous version if you can. Back up your saves. Just copying the folder to a USB drive every night after you finish playing will save you the heartache of losing so much work on a save.
I agree that running around de-aging and resurrecting hundreds of Sims is undoable! but hopefully you have an old version. The game keeps 5 previous versions of your saves by default.
Unfortunately, I had no idea it was related to the update, and kept opening and closing the game, hoping to resolve it on my own. So by that point, the damage was irreversible.
