I have used a Panasonic HDC-SD60 video camera for several years which results in .MTS video files. Prior to my upgrade to Windows 10, Windows Explorer used to process these files perfectly. Similarly Microsoft Moviemaker could process these files which I could edit then save with no problems.

Since the move to Windows 10 (I can't think of anything else which would have affected it) the MTS files can still be viewed fine by Windows Media Player, MPC-HC or VLC media player but I get strange visual effects when view with Photos or Films & TV

But my main problem is that I use Moviemaker to do my video edits and save the edited file. Since the move to Windows 10, Moviemaker still allows me to read and edit the .MTS files OK but, when I save the edited video, the resultant mp4 file cannot be viewed properly by any of my available software. I see the video but it has these strange visual effects like what I get when I open the MTS files with Photos or Films & TV