Missing piece of shredder

I believe that it could be one of two problems. First of all, and the painfully obvious one, do you have the red power switch in the on position. Try moving it to different settings to see if it does work at all. If it does, put the switch back in the center position and try shredding again. If it doesn't work, then you may have a faulty shredder. (This and the following are believing that you have a new shredder and you are trying to get it to work for the first time.) Second, if you lift the unit off the paper bin and look on the bin, you will see a slight protrusion, like a "tab." When you place the unit onto the bin, this tab must be aligned with a slot on the shredder unit; the slot will have a small strip of silver metal inside, it is part of the safety mechanism. If you are using a trash bag - to make for easier shredded paper disposal - you might have to use a bit of pressure to make sure the tab makes contact with the little piece of metal. You also may have to turn the shredder unit around 180 degrees and re-seat the unit.
If it still doesn't work, call the service/warranty/support department and find out what you need to do next.

Who makes it? Will need model and manufacturer. Not all shredders are the same.

screw a small screw into the piece in the back right corner of the basket that the shredder fits on. This will adjust to the height needed to make the shredder run.

had mine in pieces two hours ago... look underneath the label stickers their is another screw holding the box together... you problem sounds easily fixed mine is the Nylon cog has stripped itself a worldwide problem and one that fellows is ignoring..pity they are are not like Toyota on their recalls!

UK dissatisfied customer

Inside the motor assembly there are a series of nylon cogs , a large one of which interacts with a metal one.  This is the most likely place you have one or two teeth missing from the large nylon cog that drives the shredder blades.

I have a P600C-2 wastebasket - and the unit only runs in reverse. We need to put our two pieces together!

Check the switch (thin shiney metal strip on the side) is in correct position with full flap bar. A schematic drawing at GBC web site can help to locate these parts.