After scene in the Underforge is complete the game crashes right at the moment when the scene should cut to Ysgramor's Tomb. I've tried to vary the outcome, but it's useless. It's very annoying, I can't finish the Companions Quest without going forth.

Mods? Game cache verify?

I have more than 100 mods, all through Steam, but none that I would think conflict with the quest. And please excuse my ignorance, but what is game cache verification? Where would I look for that?