As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAIN CABIN DOOR OPENED DURING TAKEOFF ROLL, RESULTING IN AN ABORTED TAKEOFF. ON INSPECTION, THE CABIN DOOR HANDLE SPLINES WERE FOUND TO BE PARTIALLY STRIPPED. THIS DIRECTLY AFFECTED THE PROPER ROTATION OF THE HANDLE LATCHING ASSY OF THE DOOR THUS THE UPPER AND LOWER LATCHES DID NOT ENGAGE THE FUSELAGE.