[FIXED] Error Code 123:4a01697a / Welcome Wagon LE

Yesterday after launching the game I received an error code after loading my legacy save, but I figured since it was working fine that it must be insignificant, and I didn't note the error code. That save was working perfectly fine until yesterday, and I didn't change anything other than playing it. Like I said, despite the error code pop-up I was still able to play in the save last night. Everything worked fine. Today I went to pull up the EA app to launch the game. The EA app would not launch, and the desktop icon was missing, replaced with the "piece of blank paper with a bent corner" icon instead. I tried restarting the computer multiple times, I tried uninstalling the app three different ways (to reinstall it) and it would not uninstall. After trying every troubleshooting I could think of, my husband suggested a system restore to last night. So we did that and it broke my entire computer, sending me into a frenzy of panic. We couldn't get my computer to work, it was only showing blue error screens. Finally my husband fixed that by finding a way to cancel the restore. I then found a way to force uninstall the EA app through an install/uninstall troubleshooting program on the support.microsoft.com site. I then reinstalled the app, and when it launched I reported the issue and did an app recovery. The EA desktop shortcut icon resolved itself. To see what would happen now, I launched the Sims 4. Everything was fine, except after loading my legacy save, I received an error code message again. This time I noted the code, it is 123:4a01697a:4adea999. I believe the game would still work if I ignore it and play anyway, however I don't want to continue playing if there's a bigger issue here that's going to cause me to lose my save. And I'm just assuming this error code is what caused the EA app to crash the way it did. But I guess it is possible that it's not related? Either way, I need more information about this error code and how to proceed. I do backup my saves but not super often. I really can't lose this save, it has years of progress.

And yes I do use mods/cc and curseforge. All of my mods are updated and everything was working fine before yesterday. I didn't download any new mods in that time frame.

Product: The Sims 4
Platform: PC
Which language are you playing the game in? English
How often does the bug occur? Every time I resume the game.
What is your current game version number? 1.99.305.1020
What expansions, game packs, and stuff packs do you have installed? Most of them.
Steps: How can we find the bug ourselves? Go into my save and click resume.
What happens when the bug occurs? Error Code 123:4a01697a:4adea999 pops up as I'm sent to the world selector screen instead of loading into the household shown on "resume" button.
What do you expect to see? 
Have you installed any customization with the game, e.g. Custom Content or Mods? Yes but testing showed the custom content and mods weren't involved.
Did this issue appear after a specific patch or change you made to your system? No.

Edit By Crinrict: Added Tag to Title