User blog comment:Icemandeaf/Glitch in Sims 2 Game/@comment-4568327-20140316165704

Sims floating off the ground usually occurs when the Sim's height exceeds or falls short of the height the animation uses. For instance, if we created a hack that allows children to play the guitar, but didn't create a separate animation for it and instead linked the interaction to the animation adults use, the child will "levitate" off the ground to play the guitar, because it's using the adult animation and thus levitates so the arms and legs can roughly match the animation. It's similar to using the Sim Modder to age up or down a Sim, delete the Sim using moveobjects, and then retrieving the Sim by saving, quitting, and reloading the lot.

Normally, when a Sim ages up, he/she will *poof!* into his/her new appearance. Seeing that didn't happen, I'm quick to blame it on either custom content or corruption. If you have a back up, restore from that, disable custom content, and age the child up again. If you don't have CC, or if you disabled it and the problem still occurs, it's probably corruption.