Question / Help Why does my game video captured with OBS have a black screen in iMovie/WindowsMovieMaker?

[JurikKaehler]

I am capturing games on my Windows 10 PC with OBS and x264 codec. My problem is that as soon as I import a video.mp4 file to iMovie or WindowsMovieMaker for editing, it is black, but has sound. In iMovie is even the preview in file selection of import media black.

But when I watch it with Quicktime or Windows Video it works without a problem.

A while ago it worked - but I do not know if it was my upgrade from Windows 7 to Windows 10 or a newer version of OBS.

Things i tried:

• export it into .mov with Quicktime - didn't work - after rendering an non sense error message á la "did not work"
• reset OBS settings
• deinstall and install fresh OBS (with default settings)
• download h264 codec on windows, but it's just an .exe file - dunno what to do with it

So what am I doing wrong? Do you have any questions or need informations to help me that I didn't provided yet? Is this OBS Windows 10 Support - Information thread still up to date?

Update: Tried to capture a game video with Windows 10s new game capture feature and Windows Movie Maker has same problem with this video as well. Black screen -.-
Looks like OBS is not the problem.