I recently encountered this issue when I opened up the app at about 9pm EST and it showed WoW needed an update. Okay, fine. This stupid error pops up in my face saying to run as an administrator. Just one problem: I AM running as an administrator. I’ve uninstalled and reinstalled the app, nothing. I’ve uninstalled WoW, and now can’t reinstall it. I created a new administrator account, and it still has the same problem.
The issue pops up for all things relating to WoW only: the retail game, classic, the Midnight beta, the whole works. I installed another game - Hearthstone, if it matters - and it worked just fine.