First time i entered the game i had configured the video efect and resolution settings, then i closed the game, and when i turn it on again i'd lost all the changes and had to set them again...
the game is still playable, but its a little tedious set the configuration everytime i log in hehehe
Follow these steps:
1) Restart your PC
2) close your Torrent client and move your WoW folder away from your Torrent's download destination
3) now right click on WoW folder> Properties> remove "read-only".