Re: Solo sims in "Unplayed Sims" are disappearing

They are homeless.

I just excluded some homeless sims (unplayed) from my game and created new to the neighborhood.
At last twenty sims disappeared from my game and all made by me.
The most funny was after that because the own game created new sims but I didn't do that.

Yeah, then it's the bug described in that link. You need to move them into a house or they'll disappear once you reach a certain amount of Sims (dead ones also seem to count)