After upgrading to Win8.1 my copy of minecraft is unplayable in any version. Specifically it starts up just fine but once the level is loaded (any level) the mouse is incredibly random and the keys rarely work. The mouse seems to now only skip from looking straight up, straight ahead, or straight down. Needless to say it only takes the slightest of movements to go from looking up to looking down. It's 1 notch of movement of the mouse to move your view 90 degrees. Turning the mouse sensitivity to 5% allows me to look ahead if I make the smallest movement I can, but when looking straight ahead for more than a second massive crippling lag hits me. As for the keyboard, it will occasionally do the key I pressed (jump seems to be the only reliable one) but never after looking ahead and getting lagged (it never does recover unless I tab out, forcing it to go to the esc menu). One last thing: back in the main menu in options the scroll bars are messed up if I click on the bar and try to pull it up/down, but work fine if I just use the mouse wheel.

My first thought after realizing it wasn't just 14w17a but rather just minecraft in general was to blame the mouse drivers. But then the mouse works fine in every other program. My next thought is the version of Java doesn't work in 8.1. Yet it loaded just fine. Should I check my video card's drivers? Let me rephrase that: considering all my other games work fine it surely can't be the video drivers, right?

Also I checked to see if this was already reported but most of the other reports say the launcher failed whereas I got as far as spawning in a level before it all went to hell.