I have seen several posts regarding USB connection lost, lost calibration etc.
I had a sled not keeping up followed by lost usb connection and the warning that the machine had lost it’s calibration. I was quickly able to determine that the machine was still in calibration however I could not restart the cut from the GC line it stopped on, the motors would hum and the lost usb connection would come up again. I stripped out the already cut Gcode and restarted the file, the motors would just hum. I went to line 2 of the new file and it started to cut but the units changed to inches, I stopped it before damage was done. Changed the units back to mm and restarted the file on line 1, cut proceeded normally. This happened three times (three separate events) the same way. Now ultimately the sled not keeping up was caused by my ghetto sled weight setup hanging on an already cut pocket. But this problem happend twice while cutting and I ran into it again when I shutdown cutting last night because I was too tired. If there is a large amount of GCode between the start and your goto line this is the result I am getting in the most recent version of webcontrol. You also have to start from home when restarting. I even tried starting the original full file and then using the goto feature and had the same result. So you have to shorten up the file and then you may need to play with it (switch to another line and then back to line 1) in order to get the cut down file to run.
So part of this is a bug report for Webcontrol the other part of this is to hopefully help others, I have seen several related posts regarding webcontrol.
If your maslow stops, once you make it safe, take a picture of the webcontol screen, you will need the line number it stopped on and you may need the home position, I did have that get lost once in all of this as well.
I have a work around now but I hope this helps someone else.