On my other computer, I had the black squares underneath my sims, but the shadow fix by Nopke fixed it completely. Now after finally fixing my current primary laptop, I have an issue that the shadows underneath the sims are just blank with this mod or without it. Anyone have any tips? My specs are as follow:
I have the game set to use the NVIDIA

Processor Intel(R) Core(TM) i5-7300HQ CPU @ 2.50GHz 2.50 GHz
Installed RAM 8.00 GB (7.87 GB usable)
Display: Gtx 1050 and intel HD graphics 630
Product ID 00325-96169-98511-AAOEM
System type 64-bit operating system, x64-based processor
Pen and touch No pen or touch input is available for this display

Did you use the graphics rules maker? Because that has a button to disable sim shadows, and that could be what happened. You can try running it again, making sure that box isn't selected. Also, make sure shadows aren't turned off in the game settings.