Workaround for a bug introduced in the patch

[Jasoran]

You can find this solution if you surf the Blizzard tech forum for a while, but I thought I'd post it here for those who haven't seen it or haven't realized it might apply to the problems they're having.

Do the following:
* Exit the game.
* Look inside your "World of Warcraft" directory.
* There is a folder named "Cache". Open that.
* There should be a folder inside there, named "WDB".
* If there isn't, create one manually.
* Now start up the game.

For me, this solved issues of quest logs seemingly being wiped and various addons being unable to remember item data. For others, it's solved problems of their characters being invisible and their gear being question marks. So it's an amazing cure-all.

[Jora]

Hmm, yes, seems like for some weird reason the cache files are missing.
Stupid by Blizz to use a buggy old version on live.