My attachment will not stay in the motor unit of my hand blender.

If you are unable to fit any of the attachments to your hand blender there may be an obstruction within the attachment area of the hand unit.Check inside the base of hand unit and ensure it is completely white and there is no obstruction visible within the gap. If you see anything inside this area, carefully remove it with tweezers or a similar tool. Your hand blender should now accept tools.