immortal alduin even wth dragonrend

[Atmisp]

im using unofficial skyrim patch

[Willow Rivers]

I am assuming you are battling him up on the Throat of the World, this is a long time known bug. All you can do is reload a save before you battle him and try again.

Wait for his speech to finish before you attack him.

[Charm Quark]

What Bixillaria said, you'll have to reload, probably.

[Ilja]

There is another solution. Alduin is set to be invincible, until the battle begins. The game does not always remove this effect.

Simple solution is to do the following:
- Open console right after battle begins.
- Target Alduin trough console window and click him with your mouse.
- Type: disable [ENTER] -> Make sure he disappears.
- Type: enable [ENTER] -> He will come back.
- Close console.

This routine will refresh him and remove obsolete effects from previous scene. Note that I do not usually recommend using console in quests, but this is a known problem and method is considered safe.

[Atmisp]

thanks guys