When you go to the Skal Villiage if you see Dior the Woodcutter talking to a woman in town about the Blacksmith DO NOT interrupt the two of them. If you interrupt them in the middle of that conversation they freeze there and Deor will never talk to you making it impossible to pick up an essential quest to get to the part about Stalhrim smithing. I don't want to spoil it any further than this but I just lost two hours of play and a lot of stuff to this glitch and I would hate to see anyone else lose their progress or possibly never have the option to smith Stalhrim.

Hmm, I can't say this has happened to me. I shall investigate

Thanks for the heads up. Is this your first DB run?