Cause:

Solution:

1) Remove the mouse ball from its compartment by rotating the retaining ring in the direction indicated by the arrows on the ring.
2) Remove the mouse ball and wash it in warm soapy water, delicately scrubbing the surface clean to remove any oily build-up.
3) Inspect and clean the mouse ball compartment and rollers using a mouse cleaning kit.
4) Reassemble the mouse and secure the retaining ring by rotating it in the opposite direction from the arrows.
5) Test the mouse's movement.