I'm currently doing a new playthrough on SKyrim after 1 year of not touching it and so far everything is running smooth with 200 mods. No crash no freeze almost no gamebreaker bugs everything perfect.
Sadly I'm currently doing the Alduin's bane quest and i'v come across this popular bug where alduin is invulnerable to everything even dragonrend (can't use dragonrend on him no blue effect it just doesn't affect him.
So since it' s a well know bug i tried using the well known fixes to this bug: reloading earlier save and wait till both dragons stops talking, fast travelling to high rothgar then go back to the thoat of the world, fast travelling to whiterun and wait some time then go back to the battle, redo the cutscene entirely... and... Nothing.
I don't know what is wrong but nothing worked for me and alduin is invulnerable to everything, can't damage him, can't even use dragonrend... NOTHING !
after 3 days trying to find different solution on every possible forum i found, i finally decided to post my problem here hoping someone have a solution to this frustrating bug.
Thx to anyone who will answer or even just read this post.