I have been using the MK3 controller with USB connection to various laptops for years without much trouble. But since yesterday I had the PC lose connection to the controller twice. Nothing bad happened, the router just stopped moving. I could reconnect the controller, spindle stopped, and I could restart the program without position error.

Any reason for that to happen other than an obvious USB problem? I did replace my old 6 foot USB cable with a 10 foot cable a few weeks ago, but both are double shielded with ferrite beads on both ends.