Disabling P2P on World of Warcraft Downloaders on PC
Please Note: It may or may not be necessary to disable peer-to-peer functionality on both the Blizzard Downloader (or Updater) as well as the World of Warcraft client.
Open the Blizzard Downloader.
Click “View” and select “Preferences”
Uncheck “Enable Peer-to-Peer Transfer”
The Blizzard Downloader should now say, “Peer-to-peer sharing is disabled”