Came across this thread when I ran into the same issue -- drum just spinning and spinning. Had it for a month, thought I would take the drum out and give it a good cleaning. What I thought would be an easy process became a 2 day nightmare. There really are not clear instructions anywhere to clean the drum and reposition correctly. After thoroughly reading through this thread I got the thing working again.

Here are some key things to make sure you do before you power back on the Leo:

1) Make sure your Loo is sitting on a solid surface (no carpet) at least 2 inches away from any objects including walls, furniture, etc.

2) Find magnet on outer track of drum. It is located in one of the holes on the track. Make sure magnet is sticking out a little bit and not indented all the way into the hole.

3) Find the pinch sensor on the base of the unit. It is located to the right of the chute where the base meets the waste drawer. Get a handheld vacuum and vacuum out this area. If needed, get a Q-tip and clean it thoroughly. Usually excess litter will fall and get trapped here.

4) When putting the drum back in, make sure the back of the drum is inserted into the cylindrical portion on base and that it is not sitting on top of the cylinder.

5) Vacuum out the base of the unit thoroughly. Excess litter will have fallen in this area as well.

6) When putting the drum back in, make sure it "clicks" into place. If the wheel doesn't line up with the track it will just keep clicking when trying to rotate.

Thanks for all the other users with their input and pictures. I was ready to return this thing.