When you have to deal with repairing mp4 file, start with making a backup of the initial video file to be able to access it whenever needed. It is possible to play the copy in a different media player to find out if there is an issue with the application itself or with the file. In case the mp4 file was either downloaded or transferred recently, then getting a new copy can help solve the issue of the incomplete transfer. When the video file is unavailable, one has to see if the storage of this file has enough free space available and if the other files from the same source open without problems. The corruption of the MP4 file can be fixed by using special recovery software in case the damage is not serious. Notchox can be used for recovering video files.
Store the recovered video in another location.