importing.mp4 in Cakewalk by BandLab Posted Tuesday at 11:14 AM I do mp4 all the time, but it is H264 inside that container. MP4 is not just one thing. And a codec might be missing. It maybe just be sound encoded that is not supported to fail. But if no other solution you can use AnyVideoConverter Free https://www.any-video-converter.com/products/for_video_free/ You can convert to just about anything to anything. I do mp4 from youtube downloads too, works really well.