Start your Launcher ASAP, there is a 'reconfigure game files' routine that is run right after the launcher tools are updated and it warns that it can take up to an hour to complete. Completion of the reconfigure routine is mandatory before you are able to play the game.
If you forgot to upload your logs from a recent fight, then do it before you reconfigure the game files as all game logs are deleted during the process. Fortunately we tend to use Live Logs RGT so I lost nothing!
Then, whilst that all happens, go update your addons and watch the extra 0.5 GB download tick by.
You have been warned.
This is screwing me, my PC crashed and now as I load WoW the Laumcher Updater keeps crashing, arrrgghh!!
Lol mine has been download about 6gb of files - dunno why but it's depressing