I seem to be having the same problem. Before I got the Sims 4 City Living, screen-shotting with the PrtSc button was perfectly fine. Now, after downloading the new expansion pack, I can't do it anymore. I have tried several things already, such as, Ctrl+PrtSc, Ctrl+Alt+PrtSc and Alt+PrtSc. None of these seem to work. I just want something quick and useful rather than doing so many steps at a time. plus, I don't want to use the C, that you can use in the Sims.
Thank you.