Re: Keep getting pop up "A serious error has occurred while loading..."

@realsmolnutt  Your dxdiag is full of crashes of the graphics driver, so that's the place to start.  Since you have an older driver installed, you can simply clean-install the new one, provided by Nvidia here:

https://www.nvidia.com/Download/driverResults.aspx/224154/en-us/

Run the installer as an admin: right-click the download and select "Run as administrator."  Select the Custom (not Express) install method, and check the box to perform a clean install.  Restart afterwards and before trying to play.

Please do keep OneDrive syncing paused while testing.

Okay I have just done everything that you said, ran as admin and did a clean install. Restarted my PC after everything loaded up and then finally tried to play the game again and nada. Still the same thing is popping up... My OneDrive was paused through all of this as well. I appreciate all your help!! 

@realsmolnutt  What antivirus do you use?  Either let me know or try disabling it before launching the game.  As long as you don't do anything else at the same time, your computer should be safe.

If that doesn't help, please create a new admin Windows account and try playing there.  It should be local, as in, don't link it to your Microsoft account, and don't bring over any data from your current account or download any content.  You'll be able to launch Sims 3 without reinstalling anything.  Please leave your antivirus disabled during this test too, but don't forget to reenable it afterwards.  Let me know how it goes.

As far as I know I just have the default windows security that comes with Windows 11. I did an exclusion for my sims files in documents and on the drive hoping that would work. I have now just disabled OneDrive all together because I am so scared that It's what's causing all of this even though I have it paused. I am going to try and launch the game again with OneDrive now completely disabled but I do not have high hopes. If i am supposed to do something else for the anti-virus software please let me know because I am not completely familiar with all of that.  

@realsmolnutt  This guide is for Windows 10, not 11, but it covers the standard options for Controlled Folder Access, the feature of Windows Defender that typically causes problems:

https://crinrict.com/blog/2019/03/windows-10-defender-controlled-folder-access.html

The guide is also for Sims 4, but you can replace TS4_x64.exe with TS3.exe wherever you see it.

Long time since I've come on here because I simply got so upset I had given up but I absolutely love this game and very much want it back. I did what you said and still it has not worked. Something that I have noticed is that when I delete the sims 3 file in documents, load up the game and then right away start a new save it will work! BUT once I close out after that initial load up it goes right back to what it was doing before. Something I forgot to mention is that I have Google Drive connected to my computer and backing up my files as well. I thought this might be causing an issue but I haven't seen a way to pause the syncing like I can with OneDrive although I have turned OneDrive off all together. I'm really hoping you will still be willing to help me with this because I am just at a loss.

@realsmolnutt  Here's how to pause syncing:

https://support.google.com/drive/answer/13470231?hl=en#zippy=%2Cpause-sync

And yes, I wouldn't be surprised if Google Drive syncing were the issue.