the file if it arrived via an unsolicited email, text, or suspicious website.

: If the file is already on your system, run a scan using Windows Defender or Malwarebytes before attempting to play it.

: If the file ends in .exe , .zip , or .scr but is named "video-18mp4," it is a virus.

Where did you encounter this file name, and are you trying to or identify its source ?

: Some social media or messaging apps (like WhatsApp or Telegram) rename media files during caching or encryption , resulting in alphanumeric strings that may include the "mp4" tag in a non-standard way. Safety Recommendations: