I have problems in growing up one of my adult male sims (or male sims in general, but i have only tested on this one sim). Right the second when the "grow up" shows up, the game crashes. I tried looking up if other people have the same problem and tried their fixes, but they didn't help.

I have tried
a) changing the sim's hair to Maxis
b) took off my default skin the sim has

But neither helped. What should i do? I don't think i have any hack interrupting the growing process as well, since it only applies to adult men growing elder, all the other sims grow fine.

Have you tried going to elder men in CAS or Body Shop to check and see if that area is working. The one time I had this issue CAS and Body Shop would also crash on elder male and I had to do a 50/50 search of my elder male cc, an outfit file had randomly corrupted. Sometimes moving the download folder can cause a file to corrupt or even a computer hiccup. Since CC is the major cause of crashes I would look there first.

I believe it is most likely something in the downloads folder. My game has never crashed due to anything else but cc (except for broken hardware).

And it may not make any sense at all, but what I found last night is that I had a male hair style with both the original and an edited version of the mesh in my game.

Stupid mistake indeed - but the funny thing is that the hair style only created problems when the male sims tried to eat And I only realised that the 3 males giving me problems had the same hair style after extensive investigation! Removed the one mesh, and all 3 of them are eating like kings now.

Ah, when i looked at elder men's clothing on Bodyshop, it indeed crashed. So it might have something to do with that. Thank you ;v;

Check your downloads folder if you have file called "uhkjhihjkj(11)" and delete that. If you open it in SimPE it only contains: 1534 CRES's. That file likes attaching itself to Sims and sometimes when people upload clothes they think it's the mesh for those (it's not). It can appear with different names too but you can recognize it for its size being 6.64mb. Here's some more information about it.