Last UI Exception

So, I've been having issues with a Last UI Exception that keeps popping up in my Sims 4 folder, and I'm not sure if it's salvageable. Here's the story: When I bought High School Years, I was hit with the second-world bug and ended up having a second Copperdale. I eventually learned how to disable it, but when I tried, it ruined my save file, and I was told it might have relied on the second Copperdale. It wasn't too big of a deal, and I could ignore it even though it was annoying. Luckily, I had a backup save file and continued playing. About a year passed, and the Rent pack came out, and I could no longer travel to or from the second world. I can travel by being invited to a Sim's home, but I cannot travel there alone. I can also travel out of it by clicking on the travel option directly from my owned properties window, but I cannot travel by traveling to the world map as it freezes, and a Last UI Exception appears in my Sims 4 folder (not mods). I play with mods, and I've tried playing vanilla after repairing the game, and I am still getting the UI Exception while trying to travel to the second world.