While most folks assume watching MP4s on Windows 11 is straightforward, there are plenty of snags that pop up. Maybe the default Movies & TV app refuses to open certain files, or perhaps you’ve had trouble with laggy playback or missing codecs. Sometimes, Windows gets a bit lazy with its built-in support, or you just prefer a different player that handles formats more reliably. Whatever the reason, knowing how to troubleshoot and set things up properly can save a lot of headaches.
Getting your MP4 files to play smoothly often boils down to choosing the right apps, updating codecs, and setting defaults properly. Because, of course, Windows has to make it harder than necessary sometimes. This guide covers everything from using the default app to installing a powerhouse like VLC, including some insider tips to actually get it all working without fuss.
How to Play MP4 Files on Windows 11 — Real World Fixes
Open the Movies & TV App and Make Sure It Recognizes Your Files
First, find the Movies & TV app in Start > All Apps or just search “Movies & TV” in the search bar. Double-click it, and then navigate to your MP4. If double-clicking the file doesn’t open the app or play, right-click the MP4, choose Open with, then select Movies & TV. Sometimes the app refuses to recognize new file types if it wasn’t the default, so setting it as default for MP4s can help. You can do that by right-clicking the MP4, selecting Open with > Choose another app, then picking Movies & TV, and checking Always use this app to open.mp4 files.
Update or Reinstall Codec Support or the App
Sometimes, the issue isn’t the app but the codecs or the Windows components. Check for Windows updates in Settings > Windows Update. If you notice your MP4s still won’t play smoothly, consider installing a codec pack like K-Lite Codec Pack. Just download and install it — that often fixes missing codecs or playback glitches. Also, updating the Movies & TV app via the Microsoft Store can help if it’s an app bug.
Try Using an Alternative Media Player (VLC is the king here)
If the default Windows app isn’t cutting it and updating codecs didn’t fix things, installing a third-party player like VLC can be a game changer. VLC’s support for nearly every format is well-known. To install, grab it from here and follow the setup wizard. Once installed, you can make VLC your default player by right-clicking an MP4, choosing Open with > Choose another app, then selecting VLC, and ticking Always use this app. This usually bypasses Windows’ sometimes flaky built-in support.
Ensure Drivers and System Files Are Up to Date
Laggy or glitchy videos? Sometimes it’s a graphics driver that’s out of date. Check for updates in Device Manager > Display adapters. Right-click your GPU (like NVIDIA or AMD), select Update driver. A fresh driver can fix performance issues and ensure your hardware handles media better. Also, run sfc /scannow in PowerShell (admin) just to make sure your system files aren’t corrupted — weird glitches can sometimes be Windows damage or missing files.
Convert or Repair Corrupted MP4 Files
Not sure why the file’s not playing? Could be corrupted or improperly encoded. Try using a tool like HandBrake (https://handbrake.fr/) to rip or re-encode the MP4. Sometimes, just re-encoding fixes playback issues caused by weird encoding quirks. Or, if you suspect corruption, use a video repair tool like Stellar Repair for Video, just to see if that helps.
On some setups, these steps don’t always work in the first try. Rebooting after updates, or reinstalling apps sometimes makes a difference. It’s kinda annoying, but once everything is updated and properly set, watching MP4s on Windows 11 gets way smoother.