The best solution is the CnW Recovery program GoPro Recovery
This program is dedicated to just GoPro cameras and works on the full range of GoPro Hero cameras, including Hero 3, Hero 4, Hero 5 and Hero 6
Why a special program?
GoPro cameras are unusual because they record both high and low resolution videos at the same time. Conventional recovery programs do not work as most rely on simple data carving. Initial development was part of CnW Recovery but in 2016 the main development became a separate program. Visit the web site, download the demo and see the good results