I have noticed this problem for a while now. It happens often but not all the time. It has to do with file indexing. The .mkv file written out to completion but when the file is played it has no run time and you can't fast forward and you can't jump around in the file. The file will play from start to finish but that is all you can do. Is there a setting I am missing or is this something that is just happening with my drive reading it incorrectly. For a version or so it will be fine then for some versions I get this almost all the time. Please let me know if there is anything I can do.