I have this odd problem that WMM 6.0 x64 suddenly decided that it is not gonna show a preview of H264/MP4 video files, reinstalling codecs did not help. However, what is even stranger is that when I dragged the video into the edit pane, and then publish, the video comes out fine, and can be edited normally. However, I would like to skip this intermediate step as it wastes time and I have hours of MP4 files to convert this way. Is there anything I could do to restore the preview pane functionality of WMM 6.0 for H264/MP4 videos?