I had similar problems with H.265. I had to load a non-standard codec to get my win10 box to view the video shot. I use Davinci Resolve and it had problems with clips in H.265 even after the codec was installed. It didn't throw errors - just hangs some and seems to choke on it almost as if I had too little RAM or similar.
This was a week or so ago...I went back to H.264 ...like night and day. No problems at all.