Aloha! I just bought a used Amazon Basics B0050BPWBQ  Shredder and the unit would run in reverse only. I contacted the seller and he gave me this tip that worked for me. Insert the paper to be shredded. With the select switch in the AUTO/I mode (or on), depress the CD/Destroyer/Reset button! This causes the unit to shred! Hope this works for others!