People with Intel graphics cards cannot play my game. What is the solution?

Are you running DirectX 11 stuff where the fallback shader is just vertex lit? Have you tried exporting the game with the quality dialogue enabled and let your players choose worse settings until it works and see the difference?

DirectX 11 is disabled in my game.

Yes, I've shared a build of the game with the quality dialogue enabled. Even at the worst settings, it's still a blue background with black unlit models.

I did find out one bit of information; if I disable all occlusion culling, then people with Intel graphics cards can see the game normally. However, shipping the game without any occlusion culling is highly unpreferable.

With this new information in $$anonymous$$d, any further suggestions?