On my second machine from Sears after the first one was DOA out of the box.
The second one powered up just great, loaded the software updates set up a test project and away we went. Made it almost 80% into the project when I got my first Cover not closed error. Opened covered, lowered, pressed Enter key and away it went, for about 20 seconds and errored again. Noticed a pattern. Seems every time the head assembly moved up at any speed it seem to cause enough inertia that it bounced the cover just enough to trip the micro switches on the cover.
After examining the switches on the cover I notices that the micro switch on left side of the cover does not extend the same distance out that the one on the right side does and unfortunately there seems to be no way to adjust them, either by loosening the screws or shimming the switch assembly. It doesn't seem to be a case of a loose cable, but I plan to check the board tomorrow as noted in the other posts just in case. Wish there has been some thought to some adjustment capability on these switches for plastic components variations or the ability to add weights to the cover, which may be just what is needed.