At the end of Repairing the White Phial when Quintus shows the fixed phial to Nurelion and Nurelion collapses and is supposed to die, well that is exactly what isn't happening. Nurelion collapses but due to him being set to essential he wont actually die! He just falls to his knees!

In the console I checked if he was essential and he is. I tried setting his essential to 0 (and I used BaseID and not RefID if you are wondering), but it didn't change him from having essential at 1 to essential at 0. Using the kill command through the console obviously wont work without changing the essential to 0 first.

While Nurelion crawls around on the floor Quintus enters into conversation with me but only gives me a generic greeting with no unique dialogue options. When I exit the conversation he tries again to speak to me a second time and still nothing new or interesting happens. Then he just gets back to doing other things while Nuerlion just crawls around. Obviously I can't finish the quest in this state!

I don't know if this would effect anything but I do have many mods installed.

Can anyone help me please?

If I were you, I would advance the quest by console command to the end. setstage MS12b 100

See the Bugs section at this link.
http://www.uesp.net/wiki/Skyrim:Repairing_the_Phial

I just tried that but I didn't get the White Phial as a reward. I then tried adding the White Phial to my inventory but I could only recieve an empty copy that won't refill. Unless I can somehow get the original White Phial this quest has become useless!

Homing in on the answer: http://www.gamefaqs.com/boards/615805-/62497626

Does anyone know how to access an essential alias?