Before opening any downloaded file from an unknown or forgotten source:

You can often drag and drop .mp4 files directly into a Chrome or Firefox tab to see if they play there. 4. Search for the Context If you found this filename mentioned in a chat or a forum:

Do you remember this filename, or are you having trouble opening the file itself?

Right-click the file and run a scan with your installed security software (e.g., Windows Defender or Malwarebytes). 3. How to Play the Video

This naming convention ( video_YYYY-MM-DD_HH-MM-SS.mp4 ) is the default format for videos saved from Telegram. Check your "Telegram Desktop" or "Telegram Video" folders.

Use VLC , as it can play almost any .mp4 format regardless of the internal compression.

Look for messages from June 10, 2022 , in your messaging apps.

Upload the file to VirusTotal to scan it against dozens of antivirus engines simultaneously.