My shredder runs continuously in the auto mode with the green LED working and only stops when I put it in the off position. Reverse does not work unless I hold it down and the red LED does not light.
I have just had this. In the centre of the feed slot on one side is a sensor set back in a small slot (a torch or good light from above should show it) which needs to be cleaned out, as it "thinks" paper is still present. I used a cotton bud pushed into this slot a few times backwards and forwards to clean it. It worked for me.