I started a new game when I installed Dawn Guard, just bought all the upgrades for property in Whiterun and found I've got no alchemy lab. Is this a new glitch with the Dawn Guard dlc? I'm on PC, but I removed all mods before installing Dawn Guard just in case of problems. I'm hoping I don't have this problem with any of the other properties as I have a assassin with no alchemy lab to make poisons.

A little search and you could have found the solution here : http://www.gamesas.com/topic/1403551-breezehome-alchemy-lab-bug-fixed/page__fromsearch__1

yes Op... i'm very frustrated too

Thanks for the link alkoriak, once again it seems it's down the the user to fix Beths mistakes.

So basically no fix.

Nope, I had to disable Dawn guard to get my alchemy lab and then re-enable it again.

Did you try those commands?

prid e4ef9
disable
prid e4ec8
enable

I know it worked for me with those 4 lines. I entered Breezehome, the lab was not there. I typed the commands, the room lab appeared . Type enter after each command.