Thank you for the info Hurz.

It does seem that if anything something is accessing the second drive, then there will be some sort of interference with the mouse. I would suggest not running anything in the background while you are playing the game. I'd also recommend performing a clean boot. Simply open the task manager and select the 'Start up' Tab. Disable everything here and restart the PC.

Minimizing access of the secondary drive will help with the hitching issue. I'd also suggest starting some programs that you might usually use one at a time to see how they affect the mouse. This will help isolate which (if any) may be causing the problem.

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV!