I tried to convert a m2ts file in mkv with VideoFab 18.104.22.168 registered version.
After the process I had a mkv with audio only.
But in the settings I have marked audio&video.
I tried to deinstall ffdshow and MatroskaSplitter wich was installed on my PC.
After that the Preview in VideoFab don't works.
Then I tried to deinstall VideoFab and after restart I installed it again.
But the same Problem.
Preview and Crop menu don't shows any video or pictures.