If you happen to shut down WinCNC in a weird way, sometimes the controller won't save the "last units" in which case it defaults to MM.

The position readout will look like this:

Technically, nothing is "wrong," it's just set to MM. If you made CAM in MM you could run this way. However, we don't typically, we use Inches (IN).

To Fix this:

  1. Open My Computer > C:/WinCNC
  2. Open the file CNC.POS
  3. Look for this line: LASTUNIT=MM (see image below)
  4. Revise the line to say: LASTUNIT=IN
  5. Save the file
  6. Close WinCNC
  7. Open WinCNC
  8. Home the machine
  9. Everything should be back to normal.
  10. Make sure to set your Zeros again

This is how WinCNC will look when set to IN (inches).