I'm at the end of the golden claw quest and was having trouble defeating the draugr overlord. I decided I needed a better weapon and more health potion, so I left Bleak Falls Burrow to get them. Now I'm back, but the draugr overlord won't leave his coffin to do battle. The lid is still off the coffin, but he won't get out. While he's in the coffin he can't be hurt and he can't be searched. Any ideas?

Most likely bugged. If you have a save prior to getting to the draugr overlord reload, get your better weapon and then go learn the word at the wall and whackitty whack the draugr!

Maybe he's kin with Belethor and won't work at certain hours.

Kidding.

Try entering again or casting something with kinetic resonance on him. Something that will make things boom. Or any spell for that matter. Or wait until the place gets a respawn. This, or an earlier save. I have no other ideas.

I'm pretty sure the word wall is the trigger for the casket opening and that without it you won't be able to get it open. A prior save is probably going to be your only remedy.

You can try laying a Rune spell on his body, and then hitting it with something (an arrow) to trigger it.

Try a master level ice spell scroll?

He's not dead, he's stuck, that, in theory, totally shouldn't work.

Did you try hitting him? Some draugr fail to trigger the script part that makes them get out, and hitting them "fixes" that. Might also be your chance to perform a sneak attack on him.

It was only meant to help him move. For example, casting it on/near an object will make it shift, maybe even enter a wall or get out of it... if lucky. When I wrote that I had in mind the dawnbreaker duplication glitch.

Yeah, I know what you meant. Dawnbreaker is an object on which physics have an impact, so casting an AOE spell will kick it out of the pedestal. Living things do not work like this. For example, the reason why it wouldn't work is the same as why any other enemies in the game don't fly off when hit by the same spell. The spell has no actual, physical impact on an NPC. But it might still work for other reasons though, so I'm not suggesting the OP not to try it out. For example, what I suggested might fail because the game might still somehow oddly render the collision of the lid as if it's on top of the casket. Trying to perform a melee hit on the draugr would thus fail, while an AOE spell might pierce through. This is all mights and coulds, so the OP should try everything before reverting to an old save, which, hopefully, isn't too far away. :/

Fair point about npcs and objects, but I'd still try my idea even if the chances of success are small . The cozy draugrs I met usually woke up after I shouted.

(If playing on PC) Maybe a console command could solve it. I'd try adding the stone tablet to the inventory. If it works, there is no need to kill the draugr.