Game crashes when entering Akh Afah Amphitheatre

[Pyojamas]

This first happened on the seventh of November (ten days ago). I joined a party finder group to run Akh Afah Amphitheatre (Extreme) to complete a Wondrous Tales entry, and when we attempted to enter the trial, after several seconds of black "loading" screen (I was still able to use chat), my game crashed to
"An unexpected error has occurred. Exiting FINAL FANTASY XIV.(17)"
Trying to log back in afterwards, I was met with the same problem several times, and after a restart of my computer was able to log in finally, back where I was before attempting to enter the trial.

I tried, then, to enter on my own and still crashed. I left the game for the night after that, and was able to log back on in the morning back where I was before trying to enter the trial.
For the following week+, I didn't try to enter Akh Afah again and it did not show up in trial roulette.

Yesterday (the sixteenth), when queuing for Trials Roulette, it happened again. Trial attempted to load, and I crashed to the same error message. A friend who was with me confirmed it was Akh Afah Amphitheatre (Hard). This time, even after restarting my computer, I was unable to log back in afterwards until some time had passed and, finally, three attempts later, I was able to log back in to the area I was in before trying to load into the trial.

This does not appear to be happening with any other trial or duty (though admittedly I have not tried all of them). The party who remains in the game is left stuck in the entry "bubble" until I am finally marked as offline, and of course then they're down a party member until it gets filled, so no one is very happy about it...

[Culfinrandir]

If it's a specific place that causes a problem I would initially look at your installation as being a potential source. You need to do a clean install of the game. You can copy over the settings so you don't lose them (there are guides online).