[OPEN] Error Code 134:f3b264bf

I'm experiencing the same issue with my game at the moment. I haven't ever reported a bug before, so I hope I'm doing this right.

Update: The recommended Sims 4_Old workaround worked well for me too. I'm going to test around a bit. Thank you!

Product: The Sims 4
Platform: Windows PC
Which language are you playing the game in? German
How often does the bug occur? Every time, I have tried repairing the game
What is your current game version number? 1.99.264.1030
What expansions, game packs, and stuff packs do you have installed? It's easier to list what I don't have installed. I have every pack except Journey to Batuu, Realm of Magic, Paranormal, Fitness Stuff, Bowling Night, Vintage Glamour, Spooky Accessoires, Perfect Patio, Spooky Stuff, Luxury Party Stuff. As for Kits, I just have Incheon Style, Blooming Rooms, Desert Luxe, Everyday Clutter, Country Kitchen.
Steps: How can we find the bug ourselves? Starting the game, load a save file but can't load families.
What happens when the bug occurs? After the usual loading screen, I'm back to manage worlds with a message that says "Error code 134:f3b264bf:78e9ac19" and to relaunch the game. The game is not playable at all. 
What do you expect to see? I'd like to be able to play the game again.
Have you installed any customization with the game, e.g. Custom Content or Mods? No, I don't. I had MCCC installed before but deleted it a while ago.
Did this issue appear after a specific patch or change you made to your system? It appeared right after having installed the latest EP with Horses.I was able to load into a family in Henford on Bagley, wanted to move to the new world and got kicked into manage worlds. Can't load families since. I should mention that I haven't played with the latest patch a few days ago, so I wouldnt know if the bug appeared even before having installed the Horse Pack.