It pops right off...I had a problem with mine when I 1st got it...I used guerilla tape to keep it on...just tape around the inside edge of the flat part of the edge..
It is intended to be pried off with a large screwdriver or the claw end of a hammer-head. If it starts to fall off on a frequent basis, just put some tape around the inside of the pad driver, or the outside of the hard plastic piece that delivers the motion from the motor.
That will usually keep it on. DON'T glue it on. It might never come off.
