It was my sim's third case that this happened: adult male, insane, red hair, short-sleeved shirt. After three days of work of not finding him, and my job performance declining quickly, I finally went out on my day off and found him in five minutes. I even did the "get to know" interaction and discovered that he was insane. I went back out to work twice, and he was no where to be seen. I went through an hour-long chat session with IT support on Origin, troubleshooting, and it ended with me landing here. I've accepted there's nothing I can do at this point.
