If you used your shredder a lot, you might want to check the auto paper sensor. There are two of them, a black and a clear one, on opposite sides of the paper slot. You will want to wipe clean the black sensor, as it may be covered in a fine film of paper dust, that the machine is sensing as a piece of paper. This may require taking apart the machine to get to the sensor, as where it is located in the paper slot it's hard to get a real clean. Just vacuuming it won't do, you have to wipe it clean.
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