Thank you for the reply Alenora.

Have you experienced this issue in any other games or programs?

There may be some other program that may be interfering with the game. As such, I'd suggest doing a clean boot. Simply open the task manager and select the 'Start up' tab. Disable everything here and restart the PC. This will make sure that no background processes are interfering with the game.

Additionally, I'd suggest making an exception on your anti-virus/firewall for Final Fantasy XIV. This will make sure that it's not interfering with the game or your mouse (if either updates, it can change how it reacts to the other).

Does your mouse have it's own set of drivers or any program that comes with it? Have you tried reinstalling those?

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