So the spindle is stuck while tool changing. Most likely you've incorrectly loaded the tool into the fork ABOVE where it should be. Hopefully, it just errored out on the Z-axis. You can easily correct this, thankfully.

To Resolve:

  1. M11C1, Enter.
  2. Hit Home button it will leave the jaws open (and lots of air will continue to flow out).
  3. Once it has homed, type in M12C1 to close the spindle jaws.
  4. Then use L110 T0 to make sure it has no tool in the controller.
  5. Fix the tool in the fork and make sure all the rest are correctly loaded (see image).
  6. You are ready to run like normal.

We found the safest way to not have it stuck in a loop is to just home the machine.