Advertisements Using Roamio. I transferred some mp4 videos from pc, with no problem. Then I tried an mkv video, from my pc, and it would not transfer, and all my transferred mp4's disappeared from my Tivo! Then, I tried to transfer an avi video, with the same result! Every time I try to transfer an avi or mkv video, any mp4 videos on the Tivo disappear into thin air.