Originally Posted by Z71bill
Drop mag - make sure gun is unloaded
Lock slide back
Flip the little sear deactivation lever forward
Flip & hold the take down
Push slide back to release slide lock
Push slide forward off the frame.
The key thing (besides making sure gun is unloaded
) is to lock the slide back. It puts the slide in the exact position to allow you to flip the take down lever.
All of my M&Ps do it too; you've got to hold it down.