Turn on Laser and the motor keep grinding against the back wall wont stop moving

I have upgraded the software and then I also want to try the rotary, I gave up on the rotary and put everything back to the way it was, updated the software to 1.2.03 now when I turn on the laser it goes to the home position of 0 and 0 but the last wont stop trying to go past the back wall is grinding the gears why is this happening