I tried to play tonight and a small patch was installed, after which my game would no longer start. The game window loads up to a black screen before locking up, resulting in a "Stopped working" error message from windows. Running debug got me the following exception.
Unhandled exception at 0x009C4526 in ffxiv.exe: 0xC0000005: Access violation writing location 0x00000000.
Same error running in Administrative mode. I'm running Windows 8.1