Board Thread:Skyrim/@comment-10207438-20130806022708/@comment-23822224-20131002073121

Lord Hadron wrote: Another annoying glitch.

Was fighting Alduin in the quest 'Alduin's Bane', only Alduin isn't taking any damage. At first, I thought the only reason why he isn't taking any damage is because my Dragonbane sword only did 31 Damage and I was playing on Legendary Difficulty. But as I kept hitting him, I noticed that he wasn't taking any damage at all and I also noticed that my fully charged Dragonbane wasn't losing it's charge either, when it should've been.

Don't know what to do :( You could try loading a previous save. Worked for me.