I can't move my sims into a house

Everytime I try to move my family into a house I click ' Start playing with this household' and the button that goes back and that one goes grey. I can still click options but nothing else really. I have no mods or anything only expansion packs and its been like this since around the start of the month. At the moment that last expansion pack that I got was University. Anyone know how I can fix this? I really wanna play sims