: Before saving, ensure the "Save as type" isn't set to "Webpage, Complete."
: Many sites use "blob" or "HLS" streaming, which downloads video in tiny chunks. This is technically superior for smooth playback but makes a single-click "Download as MP4" nearly impossible without specialized tools. The Bad: Compatibility Headaches Download Not mp4
: The most common reason for a "Download Not mp4" result is clicking a fake download button that delivers an .exe (malware) or a .html file instead of the actual video. Verdict: A Necessary Inconvenience : Before saving, ensure the "Save as type"