Cannot play the game due to "An unexpected error has occurred" crash

[Final-Fantasy]

Might want to try un-installing the Nvidia Geforce Experience app completely, and download and install just the 1660 Ti driver from the Nvidia site by selecting "Driver only".

As a last resort you could set the Intel UHD graphics to run the game then move your character to a different location and swap back to the 1660 Ti and login to see if the error goes away.

To do so, open "Nivida Control panel", select Manage 3D settings, then click "Windows graphics settings" (its a link in blue), find the FFXIV app in the list and edit it to use "Power saving" or "Intel UHD Graphics", then back in the Nvidia control panel select Programs tab, find FFXIV and select "Integrated graphics" as the default Graphics card.

I would do that and move the character out of the current area to a different one, then logout and swap the default graphics back to the 1660 Ti and log back in.

If it crashes with the in-built graphics as well, which it shouldn't, but will be poor performance, you could try reinstalling DirectX as well.

If that is a laptop, make sure the power mode is set to High Performance and not Balanced (defaults to Balanced by default).

Worth a try.

One more thing, try installing the game on your OS drive which is C:, just noticed you have it on D:, I've read this can cause issues with this game if installed on a secondary drive, might help!