I just got mine to work. I'm on PC and from other posts online it sounds like it might be due to Windows 10. What I did is I went to Documents/My Games/Final Fantasy XIV - A Realm Reborn/FFXIV_BOOT.cfg. You can open it with Notepad, and changed the value on BootVersionCheckMode from 0 to 1. Saved, restarted the computer, and launched with "Run as Administrator." None of these worked on their own for me, but the trifecta finally allowed my launcher to update.