Child disappeared even after Feb 4th patch

Heya koalabon 

To confirm, this is a brand new save that did not exist before the patch yesterday?

EXACT same scenario for me! new save made immediately after yesterday's update. the mom went clothes shopping for the family's toddler son and when she came back, the son was missing from the house, ui, and even the family photo after the game immediately crashed not even a minute after coming back from the clothes shop. so frustrated rn because I had put so much time and effort into this new family with hopes that all of the previous issues were fixed via update just to have even WORSE issues!

for me after the update my game just cannot run what so ever! It keeps giving me the Direct3D returned an error D3DERR_INVALIIDCALL! error... Even though prior to this patch the game was working smoothly until my sims too also started to disappear as well. 😭

This is a household that I made after the patch, would I need to be in a new neighborhood or delete the neighborhood and start again to see the changes?

You would need a new save entirely. If you go into Documents -> EA Games -> The Sims 2  and delete the Neighborhoods file a new Neighborhoods file will generate when you launch the game again.