Basically_Duncan It sounds like the game may have started reading a different location than the one it did previously. Here's how to find that location:
https://sims4.crinrict.com/eng/2018/07/how-to-find-your-user-folder/
If this new location is fine, you can simply move your old data there. If it's not where you want it, for example if it's now in the OneDrive folder, let me know, and I'll help you revert.
As a side note, OneDrive can reenable itself during a Windows update.
Just realized I never responded to this! It was exactly as you described! Suddenly the sims created a new file location on my PC instead of the cloud, gave me a heart attack XD luckily I was able to use the method you described and moved all the files there! Thanks for your help!
