If you still want to keep Emit and accept to change him to be "normal sim", try the method from this link (reddit)
https://www.reddit.com/r/thesims/comments/1izpual/psa_guide_for_a_fixed_playable_emit/?rdt=34077
From what I read here, you already have Emit in the family, so it's easy to do now. If you want to do this while keeping him unplayed, there are more methods to do so without adding him to the family.
I don't know about how broken your save already is, I just suggest the way to play him without a problem. Try removing the hidden trait with the current save and see if it can fix it or not. If not, roll back to the previous save before the broken, then remove Emit's hidden trait immediately.
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I haven't played the save that has Emit in my save, so I don't know if it works. But I can confirm that communicating with Emit outside the event is impossible in almost situation. For example, I can't let him "chat here", and I can't bring them together when someone invites my sim to the bar.
I'll remove Emit's trait when I want to play him, but right now I leave it as it is because this hidden trait keeps him not showing in the regular lots. (I think I should fix his outfit to blend with a neighborhood before "make him a normal sim")
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I hope this will help you fix your save and keep Emit in your story.
Thank you for the reply! I X'd out Emit and Frost already, so no going back, sadly. But my game is running smoothly again. I saw a few people mentioning some of their Townies becoming immortal and not being able to age or die on a big Facebook Sims 4 group yesterday, so something's acting a little funky. At least it isn't just me 😅
Okay, if you are okay for current save, you don’t have to roll back. But if you miss him later, you can load Emit from gallery (people already upload him) or even you save file if you back up some.
Lots of special sims are immortal to stay in the game. Some NPC from San Myshuno are too. But Emit’s speciality is more than immortal. At least you solve your save file, this is good enough!
