I'm having the same issue as many on this thread, and am VERY much unhappy right now.
I'm a self-employed computer engineer, so I know the process of troubleshooting issues after installing updates. I have no mods on my version of The Sims 4, which consists of the Base Game, Digital Deluxe Content, Parenthood, Get To Work, Get Famous, and Discover University. I have had no issues with loading of saves UNTIL I installed the latest update this afternoon. The game loads to the main screen fine, but when I try to load my main save (which was last used Yesterday), then the loading screen stutters to a halt, comes up with the screen that I have attached to this post. The first thing I did was "repair" all of the game files via Origin, and that did no good. I then uninstalled The Sims 4, and re-installed it onto a different drive. I then came across the crazy issue of succeeding to "download" the Expansions etc, but only to then fail with an error when it went to finalise them. So I restarted my Desktop, cleared out the Origin Cache, and was then able to complete the reinstallation. But unsurprisingly this did NOT solve the issue! If I start a New Game, everything is fine, but when you have many households and houses in a Saved-Game, you kind of want to keep using it, especially given it was the new patch that was solely responsible for the problem.
Below is a link to a Folder containing the Saved-Game that reacts "badly" to the new patch (I indentified it via the date and time), as well as the "LastCrash" file.
https://1drv.ms/u/s!AmPcD-ueH465i41eIU6C2lRGbF7IvA?e=6Qn0BX
PLEASE would you be so kind as to either "patch" your new update, so that it doesn't crash everyone's pre-update saved-games, or at the very least REMOVE the update from Origin so that we can all safely reinstall the game?
Because until you do, NONE of us on this stream will be "happily" playing The Sims 4 again.