A Serious Error Occurred

@21_abc_81401  As a test, please move the entire Sims 3 folder out of Documents\Electronic Arts and onto your desktop.  When you launch the game, a clean folder will spawn with no content.  (Your saves and other content will be in the folder you've moved but temporarily not read by the game.)  Don't add anything to the new folder yet; just try to start a new save and see whether you get the same error.

If the new save works, you can move the saves and other content you'd like to preserve from the old Sims 3 folder to the new one.  For any content, please move the files themselves, or the save folders themselves, rather than the folder they're sitting in (i.e. don't move over the existing Library or Saves folders, transfer their contents to the new Library or Saves folders).  If a file or folder can be regenerated with no content lost, just use the new version.  Here's a description of everything in the user folder:

https://sims3.crinrict.com/en/2011/01/faq-user-files.html

If you still get the error even when using a clean folder wtih nothing in it, please let me know what antivirus, if any, you use.  Please also run a dxdiag and attach it to a post.

https://help.ea.com/en/help/pc/how-to-gather-dxdiag-information/