Windows Media Player Not Playing MP4 Video Copied from My Phone

Windows Media Player not playing MP4 files can have several causes:

1. Incorrect codec:  Windows Media Player might not have the necessary codec (a set of instructions for decoding the audio and video) to play the specific MP4 file.  This is the most common reason.  MP4 files can contain various codecs for video (H.264, H.265, MPEG-4, etc.) and audio (AAC, MP3, etc.).  If the codecs aren't installed, WMP won't know how to interpret the data.

2. Corrupted file: The MP4 file itself might be corrupted, preventing proper playback.

3. Incorrect file associations: Windows media player not playing MP4. Windows Media Player might not be the default program associated with MP4 files.  Another program might be handling them instead.

4. Outdated or corrupted WMP installation:  A problem with the Windows Media Player installation itself could be preventing playback.

5. Hardware issues:  If the file is very large or complex, there could be issues with the computer's processing power or hard drive read speed.

6. Insufficient permissions: If the file is on a network drive or a location where the user doesn't have the appropriate permissions, the player might not be able to access the file.