You previously created this thread and were asked a series of questions, most especially about exactly which version of MS you have, but never responded. Please, at the very least, tell us the version of MS you have and include the computer specifications you were asked for before.
With more information we should be able to offer you some help!
Sorry Jeff. I was looking for a video converter to change a mp4 to mov ext. the version of Magix that I have will not recognize and will not work with this movie file .mp4.
Thank you for the additional information. Unfortunately, we still do not know exactly which Magix product and version you have!
However, I am very surprised that you need to change a mp4 to mov. mp4 is, effectively, a universal format (so playable by [almost] any video software), whereas mov requires that the user's computer has Quicktime (or similar program) installed. Why do you need to make this change? mp4 is a "container" format, so can include a variety of different codecs - at least some of which can potentially create problems.
In order to help us to help you please read this tutorial about using MediaInfo to provide a full analysis of one of your mp4 files which you cannot currently use. Please copy and paste the result of the Text view to your next post. Thank you.