VLC media player is more than a video player, this very known media player contains within it lot of tools (conversion, streaming, subtitles, …) and is known for its ease of use, but sometimes problems happen like the error “VLC Does Not Support UNDF Format” we discussed earlier.
Lot of VLC media player users noticed that after playing multiple media files at the same time or for some other reason… VLC media player opens a new window called “VLC (Direct3D output)“.
Eliminate the VLC (Direct3D output) Window
Here is how it looks, after playing a dozen videos at the same time using VLC media player on Windows 10.
As you can see I have two windows, one titled “VLC (Direct3D11 output)” and the other contains the playlist and other elements (menu, control buttons, …) of VLC media player.

To fix this, make sure you are using the latest version of VLC, then go to “Tools” > “Preferences“.

In the Interface tab, check “Integrate video in interface“, don’t close the window yet, we are going to make sure everything is fine with other options…

In the bottom left corner, choose Show settings > All.
Go to Video and check “Embedded video“.
Save and restart VLC, if you want you can even Reset settings to make sure you are working on a fresh version of settings.

Now try to play a video, problem solved!

Share this fix with your friends! Thanks a lot for your support.
Great, quick and easy instructions to follow, did exactly what it said
Hello, everything mentioned here was already configured correctly but problem persists. Even reset preferences and problem remains. It happens when opening 3 or more files (not 2 or less).