Does anyone know how to remove the windshield mounted rearview mirror?

 

With mine, it is a friction fit. Lightly tap the black cover upwards.

I had the opposite problem. When I bought my X, the mirror was loose on the windshield. I tapped it downward and now it's solid.

 

This is from the service manual. The tool is just a small flat blade that you can make (small screw driver) that you push up in the small slot at the bottom of the mount.
Removal
1. NOTICE: Twisting the interior rear view
mirror base from right to left may cause a
Mirror Remover stress fracture of the windshield.
501-D118 If equipped, remove the wire cover.
2. If equipped, remove the compass by pulling
downward on the compass.
3. If equipped, disconnect the auto-dimming
mirror electrical connector.
4. Insert the Mirror Remover between the mirror
mount and windshield bracket from the bottom.
5. Release the mirror mount from the windshield
bracket by pulling the tool Mirror Remover
away from the windshield.