Fortunate that you had saved first.
CAS is very slow since the last patch and I avoid doing too much in it as far as possible. I forgot and 'saved' a sim the other night and it took such a long time that I thought my game had frozen. Luckily, for once I was patient - mostly because I hadn't 'saved' first and would have lost hours of progress if I had quit there and then - and the game eventually came back to life.