This is very common and can occur if an update went wrong or you copied the game from somewhere else. Corrupted Files: Windows and Game files get corrupt or unusable every now and then.If they are not in a working state, the launcher will fail to load them and hence WoW will not be able to launch. Outdated Add-ons: Since add-ons are an essential part of World of Warcraft, it is possible that they are not updated correctly or are corrupt.
