December 2018
I have multiple issues. I got the seasons pack a little after it came out. I played it once and it was fine. The next day I tried and since then my game has been acting up. I stopped playing for a while and tried again today. My first issue is that I can't start a new game. I can click the button but it doesn't do anything. Alright fine, I have a bunch of files already. If I go into another save and create a household, when I try to place them on a lot the drop down says OK and the check mark doesn't respond when I click it. When I go into build/buy mode, the menu of items and buttons at the top don't appear. I also can't access the menu so I have to do Ctrl+Alt+Delete and sign out of my computer. I figured it was because of seasons so I disabled it. Did nothing. I then thought my mods were messing it up, but the Mod Conflict Detector wasn't opening so I fixed everything in Sims Studio. I opened the game and nothing still happened. I tried adding every folder in The Sims 4 one at a time to see what it was, and sure enough my mods were messing it up but I don't know how to fix it.
January 2019
Move your Mods folder to the Desktop and delete localthumbcache.package. Then test the game.