There is a glitch in the software because I have opened my cover and the bit stop spinning but the program kept running and the bit broke. I had to hit the stop button to stop it. This has happened just once but it indicates a problem in the software to me. The cover safety switch should be hard wired to stop all motors, not just the bit. The software would have to back up a few steps when restarting the project because of the delay in receiving the input signal but that is easy to overcome. Unfortunately it seems we have to purchase the Designer upgrade to get any firmware fixes for the machine. Someone correct me if I am wrong please. If that is the case this won't likely be fixed unless you buy the latest or a future Designer upgrade. I suggest that you always hit the stop button before opening the cover to be safe.