We recently ran across an issue when one of our M600s gave a warning message of "WARNING Motor Obstructed," locked into a hover mode for about 5 seconds, and started to perform the RTH function, but unfortunately crashed after hitting a tree canopy that was overtop of it.

During the time we received the error message, we immediately switched it to ATTI mode.  No positive control was gained.  Switched multiple times between P, A, and F modes and none allowed for positive control.  Once the aircraft initiated the RTH function (before it hit the tree canopy), we tried all control stick combinations to stop the motors, which did not work.  Even after the M600 landed upside down, the motors still spinning, the control stick combinations to stop the motors did not work.

Note that this message stated that there was a motor obstructed, all 6 motors will stlil spinning fine.

I understand the safety of the RTH function, but not even being able to regain positive control in ATTI mode gives you a feeling of helplessness, considering we were only 5 feet away from the aircraft.  Now we are down for about a $1,200 repair...

Sorry to hear about your aircraft.
I usually tend to set my fail safe RTH to hover, rather than land. Maybe try this in the future when you get your aircraft back.
I`m not sure what your fail safe RTH was set to though.

Hi. My new M600 was only 2 days old. All was fine and then motor Obstruction warning. It fell out of the sky from 60ft damaging camera, lens, gimbal and aircraft. Craft now says ESC no. 5 error. DJI have the logs currently.