If the file won't open, it may be corrupted or a "fake" file (common with oddly named downloads). Right-click the file, select Properties , and check if the file size matches what you expect for a video. 3. Fixing the Extension
If you need to change the actual format (not just the name) for better compatibility, use a tool like Handbrake : IPX-550.mkv.mp4
This often happens if someone manually renamed the file or if a conversion process failed to replace the old extension. Usually, the last extension ( .mp4 ) is what your operating system will try to use. 2. How to Play the File If your media player shows an error, try these steps: If the file won't open, it may be
A flexible container that can hold unlimited video, audio, and subtitle tracks in one file. Fixing the Extension If you need to change
A file named appears to have two video container extensions.
Click Start Encode to create a clean, single-extension version.