Simulation Meshing Interference

It worked! Now that I can begin trial and error to reduce as much material as possible, SolidWorks is having trouble with fillets. To reduce the stress concentrations at the corners of the very first cutouts, I want to add fillets. It varies as to when the program stops working but I can get anywhere between 0 and 3 fillets completed and rebuilt before the screen goes opaque and stops responding. I'd imagine it struggles because the geometry of the body curves through all three dimensions. Windows checks for solutions but never turns anything up.

Any suggestions? I'd prefer not to have to return to the sketch that created the geometry and add in a sketch fillet.

Thanks for that. I have seen people use the Interference Detection feature but did not realize I could use it with a single part within an assembly. I noticed you have that box checked.

I just don't understand how this happens. I use coinciding geometry to create other bodies and surfaces to make cuts, etc. so just about everything references everything with offsets and up to surface extrusions/cuts. Many of the interferences are tiny, and some are barely visible when highlighted. I do know that SolidWorks cuts corners with the graphics to increase performance so it can be difficult to tell, but I don't see how using existing geometries can create interfering bodies.