Why can't I harvest blood for Discerning the Transmundane?

I'm doing quest Discerning the Transmundane and I'm on level 15.

I've killed orc, falmer, high elves, and dark elves but I can't harvest their blood, I can only search them(loot).

I'm playing on the xbox360, game version 1.0.0.

Solution 1:

There is a known bug with this quest where the perk that allows you to harvest blood is not properly added when the quest is given.

Since you don't have access to the console on the XBOX version, you can't use that to fix this. Therefore, you must reload to an earlier save (before the quest was assigned) and hope it works the second time round.

It won't resolve your issue in this case (due to the specific way the quest is set up), but you might also consider updating the game; Bethesda has been much better about patching bugs in Skyrim than they were in Oblivion. Preventative measures can't hurt!

(Though, for what it's worth, I just got hit with this bug myself, despite an up-to-date version + the unofficial skyrim patch)

Solution 2:

According to the UESP wiki, this quest could be affected by this bug:

You may not have the "Harvest blood" option despite having the Essence Extractor in your inventory.

For those playing on the PC who have encountered the same issue, the console command to fix this is player.addperk 79af5.