Sim will not finish writing horror book

Sim is trying to complete ghost historian. They completed the first two horror books. They began writing the last one, and every time they sit at any computer, even a different lot, they do not start writing. They completed a childrens book, and still would not finish writing a horror book. I started a new horror book,and they also will not finish that one. I tried resetting, changing aspiration and then changing it back. Nothing works and they won't finish writing the horror book.