An update on this: I have a test user on this machine that I've been playing on off and on for the last day or so to see if I could replicate the issue. I could, and have confirmed that some issue with changing inventory/item lists can cause (for Macs) the entire machine to freeze as the machine has a gpuRestart cascade.

Yesterday, I played for something like nine hours without issue. I started with nothing else running besides Activity Monitor and the Notes app to take notes on machine behavior, nor anything unnecessary connected via Thunderbolt or USB (e.g.: my backup drive, etc.). Since the system freeze was happening after about 2-3 hours of play previously, I'd change a single variable one by one to see if it triggered the gpuRestart cascade. First, I added a browser, and would switch between apps from time to time (to look up crafting or gathering information). Then, I added an app that has a GPU Renderer hang in Activity Monitor (Discord). Then, I added connecting my Time Machine drive and letting Time Machine backup. No crashes.

Today, I was still running on the test user to assess something else. I had the browser open and Time Machine backing up, but no Discord window open. A handful of hours into play, right as I was extracting a materia (and thus effectively altering an item list, which seems to be the common trigger for this), the game window's graphical interface froze. As previously, I could still move the mouse cursor (though not within the game window), and I could technically even 'click' on the round 'character' button and hear the *click* noise of it activating, but the graphics were frozen mid-animation.

I lucked out this time around, as several seconds later, everything but FFXIV became responsive again. I could test if the FFXIV window being backgrounded lowered its CPU usage as usual (it did). I looked at the /Library/Logs/Diagnostic Reports window, and two new ‘Kernel_[date]_[machine name].gpuRestart’ logs were present at the time of the initial freeze. Not a full gpuRestart cascade this time, but enough to hang the game, and the whole system for several seconds. I wasn't able to Quit the way FFXIV ought to be Quit (via Log Out or Exit Game in the app itself), but I was able to 'soft' close it via the menubar.

I took some notes, and then tested whether reopening FFXIV would be functional, shaky (a crash soon thereafter), or freeze the machine. It was able to render the login window, the start screen, and the character screen, but as soon as I tried to login to my character, it was too much demand on the machine that had just recently had two gpuRestarts. The whole machine permanently hung.

I force shutdown the machine by pressing and holding the power button. I then turned it back on as per usual, logged into the test user, and looked over the Diagnostic Logs. As I expected, exactly nineteen ‘Kernel_[date]_[machine name].gpuRestart’ logs. (I have a suspicion why 19 of these logs is the equivalent of the GPU entirely failing on this machine, but again, it's only a suspicion.)

I've also talked to a PC user who also plays the game a lot, and he mentioned that he's been receiving more frequent red text error messages when item creation/transferring fails, but all it does for him is not complete the action, I can't say it's the same root issue causing dramatically different problems for PC users than Mac, as I'm not sure we're experiencing the same root cause, but I thought it worth it to mention it.

So that's where I'm at. I'm at a point where I'm just not sure I can even keep playing FFXIV. I've reached out to FFXIV Customer Service for help, but I keep getting bounced from agent to agent, and they ask me the same basic questions, all of which I've answered in the initial email. I'm also in communication with Apple Support, who's talking to the Apple Engineers, because any FFXIV error that can cause a GPU Restart cascade and take down the whole machine is something Apple needs to know about.

Anyone from Support here have any ideas? <3 I'd honestly much prefer a fix to this than just to keep talking to Apple. (Collaborating with SquareEnix means maybe a fix to a pretty terrible bug! Collaborating with Apple about a fatal bug in FFXIV is, at absolute 'best', likely to get the game no longer supported for Mac.)