Rerun the code cutting air and see what happens.
PS: If you manually move position to load a tool you cannot just restart the machine and expect the code to know you have moved position. However this does not explain the failure to go to the tool change position in the first place. It might explain the plunge into your work piece on restart though, if the programmed tool change position was actually higher than you manually positioned it. What did you set the tool change position at.
PPS: Describe the noise from the motor, in as much detail as possible, when it failed to go to the tool change position.