If you are having trouble playing the .mp4.mp4 (which looks like a double extension error), try these steps:

If you downloaded this from a forum or P2P site, it may be a clip of a live performance or broadcast. 2. How to Open the File

Many DVR and NVR systems (like those from Lorex or Swann ) use this naming convention. If you found this on a hard drive, it may be a recording from January 2002 or a specific channel marked "401."

Right-click the file and remove the extra .mp4 so the name ends simply in .mp4 .

Standard players might struggle if the codec is old. I recommend using VLC Media Player as it can play almost any video format regardless of naming errors. 3. Inspecting Metadata

, and are you having trouble getting it to play?