Sorry for the multiple posts, but I found a constant variable that always resulted in my sims and lot losing their progress. It's the World Manager editor or feature that causes it.
My reasoning ....
- My sims don't lose progress when I keep them on the lot and bulldoze their home from the build menu. The game allows us to place homes from the library, so I've been saving the lot to the library, bulldozing it, and replacing it without an issue until last night. I could then save my game without losing progress.
- Last night the lot itself was glitched, and not any objects on it. The bulldoze feature wouldn't work due to this error, so I deleted the house room by room until I had nothing left on the lot. The bulldozer still didn't work. Instead of jumping into the world manager, I used the club feature and started a gathering on another lot. My sims went to hang with their buddies, and I saved my game from there. It worked, so I quit the game and restarted it. Whatever caused the lot to glitch had been fixed in the restart. The lot was still demolished, and my sims didn't lose their progress. I could then replace the home from the library files and continue to play.
Things not affected by the world manager/editor
- newborn babies will stay as newborns, although their mothers can be reset to a time before they were born. This means multiple babies if you keep using the world editor after each birth.
- Character progress on lots not associated with yours. A sim from another home died on my lot, and my sim called her ghost forth and eventually invited her into his family. The 533 glitch happened and I entered world manager to try and save the game. It kicked the ghost from his family, but she returned to her original home. My lot and sims reset to a point before she died, but she was still dead and living with her old family.