Use VLC Media Player or Windows Media Player.
Before opening, run the file through an antivirus or upload it to VirusTotal to ensure it isn't malware disguised as a video.
If you found this file online or received it from an unknown source: Ajb08406 mp4
Since the name is non-descriptive, you can check the file's metadata to learn about its origin:
If this is a personal video (like a security camera clip or a screen recording), it's best to rename it to something recognizable: Select the file and press (Windows) or Enter (Mac). Use VLC Media Player or Windows Media Player
The .mp4 extension is a universal container format compatible with almost all devices.
Use a tool like MediaInfo to see the specific camera or software used to encode the video. 2. How to Open the File How to Open the File A real MP4
A real MP4 should typically be several megabytes (MB) or gigabytes (GB). If the file is only a few kilobytes (KB), it is likely a broken link or a shortcut, not an actual video. 4. Renaming and Organizing