I am having very similar issues with the same application event error. My game freezes and either disappears and goes back to desktop, but I am still able to hear the game, or I instantly crash and the game closes. It happens most often when I zone into an instance, but it happens completely randomly 3 - 4 times a day.

Faulting application name: ffxiv_dx11.exe, version: 1.0.0.0, time stamp: 0x55a68eb2
Faulting module name: ffxiv_dx11.exe, version: 1.0.0.0, time stamp: 0x55a68eb2
Exception code: 0xc0000005
Fault offset: 0x0000000000145691
Faulting process id: 0x80c
Faulting application start time: 0x01d0c4e0e8580492
Faulting application path: Z:\SquareEnix\FINAL FANTASY XIV - A Realm Reborn\game\ffxiv_dx11.exe
Faulting module path: Z:\SquareEnix\FINAL FANTASY XIV - A Realm Reborn\game\ffxiv_dx11.exe
Report Id: 888989bf-30d8-11e5-a716-fd8d704e9abb