I struggled with peeling hard-boiled eggs literally all my life until I finally realized what the problem had been right along. If eggs are stored below a certain temperature, which I estimate at 38F though I have only used consumer-grade thermometers, they will not peel. And this applies both before and after cooking. Since I learned this, and adjusted my cold storage accordingly, I have had no problems, except occasionally when a batch sold through a particular retailer apparently got too cold somewhere along the supply chain. The word "freeze" is not appropriate but the egg albumen does undergo some kind of irreversible change below the threshold temperature -- and suppliers are evidently aware of this, as it is very unusual for eggs to be damaged in transit by excessive cold. But if you keep your fridge at or below 38F, you're asking for trouble.