disappearing sims?

Babies and toddlers do like to dissappear (accidental death) but they usually don't disappear from the family tree like this.

Try resetting your user files as described in the factory reset described in this post: http://answers.ea.com/t5/The-Sims-3/FAQ-Troubleshooting-Steps/td-p/714/

You won't loose anything. Just make sure to not delete any files  and make a backup.

Then before putting anything back, start a new game and see if it happens again. You can also try if turning off StoryProgression helps

Thankyou, i will try that. But this is the first baby that is missing. What i mean is on another game save, i had a 2 young adults, male and female, and then the female just went missing, before i left the game(when i frist made them), there were friends, but now(when i load the game up the second time) he has no relatiopnship with her, he didnt know her! and then i had 3 girls at university, when i opened the game, once a again i had a missing sim! but this time, the sims was just 'sent home' from university, and the sims i was playing still knew her(if i clicked on her photo in the relationship bar thing, it said call long distance). therefor i carried on at uni, hoping the i would be able to play the sim that got 'sent home' when they finnished uni, but when the loading screen came up to load back to brigeport from the university world, it actually never loaded, i left it loading for 30 minutes and then gave up! my games annoying so much i cant play any saves!

You might find some solutions going through this link: http://answers.ea.com/t5/The-Sims-3/FAQ-Game-Corruption/m-p/968290/

Also it does happen that Sims move away if you have StoryProgression activated.

OKay thankyou! i reset the factory setting and that didnt work, BUT! i will just start a new family with out story progession on see how it goes. Thank again!🙂

Hopefully it works 🙂 

Let me know.

Nope, did not work, Sims3 is really messing up now, okay so, firstly if i go in to build or buy mode and then try to back into live mode, i wont let me, so i have to force the sims to close in the task manager. secondly, i made a female sim, played her, then left the game, and guess what happened when i went back on the game...she disappeared, and there was no playable sims in the family. im really stumped now, i have tried everything, resetting the factory settings like you said, reinstalling the game with took me a long time! and going into backup files and renaming them, nothing has worked. I love the sims and haved played sims3 pretty much since it game out, and never had a problem this unfixable☹️ .

So you started a brand new save game and this happened again or did you just start a new Sim in an existing savegame ?

I started a brand new save game, also, i reinstalled the game again hoping it might work, deleted all Costom Content and the saves from before... still the same proplem...   ☹️ and i also can not exsit buy/build mode and it just loads into live mode for ever☹️ HELP!

Did you clean out your registery when you reinstalled ?

Whats that? and where can i find it?