I have exactly the same problem now so that old problem has come back. And it really only appeared after the latest update. Before that there was no problem. So how should this problem be solved? Preferably though, I would hope that this problem would be fixed ASAP. I would like to be able to switch to the desktop side of the game without having to shut down the game. And I'm playing my version of TS4 at my PC and I'm not gonna change it.
And I have almost all the add-ons, by the way. Only a few kits and the buggy love expansion pack are the ones that I do not have, yet. So it's definitely not because of this latest expansion pack. But very likely just that latest update.