It’s been almost two years since Windows 11 was released and still, PC users are experiencing issues with the operating system. One of the issues that Windows 10 and 11 users are experiencing is trouble setting a default app for MP4 video files. In this Windows 11 guide, I will help Windows users with how to fix the issue of not being able to set a default app for MP4 video files.


How to Set Default App For MP4 On Windows

Windows is of the most used operating systems in the world and it is far from a perfect one as PC users often experience errors and issues with the Windows operating system. Some PC users are having trouble setting the default app for MP4 video files on Windows 10 and 11 and the following are the methods that will help players with how to set a default app for MP4 video files.

Reset Films and TV App

Films & TV is the default media players in Windows 11 and over time the app may start to misbehave which can result in players not being able to play to set a default app for their MP4 files. This can be fixed by resetting the Films & TV app.

Open Windows Settings > Apps > Installed Apps > scroll down and find Films & TV. Click on the three dots in front of it and select Advanced Options from the drop-down list, scroll down, and click the Reset button. Wait for the process to complete, right-click any MP4 files you want to play > right-click it > Open with > Choose another app > select Films & TV app and click “Always”.


Install Missing Extensions or Third-Part Media Player

Another reason why you are unable to play MP4 video files or set a default app for it is that the default video player doesn’t have relevant file extensions. You can download K-Lite Codec for the missing file extension or use Media Player Classic as your default video player to fix the issue.

Download K-Lite Codec Pack and download the basic version. Install K-Lite Codec by double-clicking the downloaded file > Choose your preferred video player > press next > keep the default settings and click next. Once the extensions are installed, set your preferred app as the default player for your MP4 files.

Alternatively, you can just use Media Player Classic as your default app for MP4 files and you don’t even need to install as it installs with the K-Lite Codec pack.

Roll Back To Windows 10

If you are experiencing this issue on Windows 11 and the above fixes didn’t work for you, then you can switch back to Windows 10 to fix the issue. Open Settings > System > Recovery > select “Go back”. Follow the on-screen prompts and roll back to Windows 10. After the downgrade, your MP4 video files will work properly and you will be able to set a default app for it.


However, this will only work if you upgraded to Win 11 from Win 10 and still have Windows 10 files on your drive. Otherwise, the “Go back” option won’t appear, and have to manually install Windows 10 from scratch.

That is all for our fixe for how to set the default app for MP4 video files on Windows 11. If you are facing errors and issues with other PC games or your PC, then also see our hub for commonly occurring PC errors and their fixes.


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