To Delete a Custom Unit
You can delete a custom unit that you previously created. You cannot delete a predefined unit. Use caution when deleting units; you cannot undo the deletion.
1. Click File > Prepare > Model Properties. The Model Properties dialog box opens.
2. Click change in the Units line. The Units Manager dialog box opens to the Systems of Units tab.
3. Click the Units tab. A description of the selected unit appears under Description.
4. Select a custom unit that you want to delete, and then click Delete. A warning message appears and lists the unit you have selected for deletion.
5. Click Confirm to delete the unit.