Previously Installed Addons

If you already have installed addons that use plugins to load with the game (e.g. ArcDPS, GW2Radial, d912pxy), I would recommend deleting them. This is because the Addon Manager uses the addon loader to load plugins when launching the game, and the plugins get stored in separate folders, not in /bin(64)/. Because of this, any other plugins in /bin(64)/ won't work --- in theory, they shouldn't break anything else, but I'd remove them just in case.