What I did was go into the World of Warcraft folder (C:/ProgramFiles/Worldofwarcraft) and deleted the entire "WTF" folder.

Reset your game client/addon settings. It's the first thing you should do with any UI problem.

I then went into the "Data" folder (C:/ProgramFiles/Worldofwarcraft/Data) and deleted the "En_US" folder in there

Essentially deleted the game completely. 20gb download inc