Xbox Game Bar doesn’t record full screen video. There is black bars all around the gameplay...

• If nothing happens when you press the Windows logo key
  + G, check your Xbox Game Bar settings. Open the
  Start menu, and select Settings >
  Gaming and make sure Record game clips, screenshots, and broadcast using Xbox Game Bar is
  On.
• If Xbox Game Bar doesn’t appear for a full-screen game, try keyboard shortcuts: Press the
  Windows logo key + Alt +
  R to start recording a clip, then press it again to stop. You’ll see the screen flash when the recording starts and ends.
  

Troubleshoot Xbox Game Bar on Windows 10

I did everything but still not recording. I can take screen shot with game bar but can't record video.

Im pressing button but nothing happens

Hello

• If nothing happens when you press the Windows logo key + G, check your Game bar settings. Open the Start menu, and select Settings > Gaming and
  make sure Record game clips, screenshots, and broadcast using Game bar is On.
  
• 
  If Game bar doesn’t appear for a full-screen game, try keyboard shortcuts: Press the Windows logo key + Alt + R to start recording a clip, then press it again to stop. You’ll see the screen flash when the recording
  starts and ends.
  
  You may also want to try checking for updates, or resetting your PC.
  
  Luck.
  

• If nothing happens when you press the Windows logo key
  + G, check your Xbox Game Bar settings. Open the
  Start menu, and select Settings >
  Gaming and make sure Record game clips, screenshots, and broadcast using Xbox Game Bar is
  On.
• If Xbox Game Bar doesn’t appear for a full-screen game, try keyboard shortcuts: Press the
  Windows logo key + Alt +
  R to start recording a clip, then press it again to stop. You’ll see the screen flash when the recording starts and ends.
  

Troubleshoot Xbox Game Bar on Windows 10

Hello btwziko,

Thank you for the response and for sharing the screenshot.

You can share here a screen recording as long as your personal information is concealed. However, for this concern, you do not have to share a screen recording as the Xbox Game Bar have already written the warning. The game's settings will not support the Xbox Game Bar to record your game play not as long as you switch into full screen borderless in your video options. As we recall you mentioned the Xbox Game Bar to be working on Windowed Fullscreen. It is by default for this game to record it in such settings. There are games however, you can play on full screen and there are others on Windowed Fullscreen.

Should you need Xbox Game Bar to be working on Fullscreen gameplay for Minecraft or specific games. Please send out feedback to both Team Xbox and the game support (Mojang Support for Minecraft).

On Xbox Game Bar, go to settings and look for feature. Please specify what edition you are playing like you have mention here: Xbox Game Bar to be available for Minecraft Java in full screen mode.

On this link for Minecraft Feedback (New post – Minecraft Feedback), please provide the same details you have mention on Xbox Game Bar.

We appreciate you have brought this to our attention. Please send feedback to request Xbox Game Bar to record game play on the fullscreen mode. We hope this will be available in the future update of Minecraft Java Edition.

If you have further concerns kindly create a new thread using this link - Create a new question or start a discussion.

Regards,

I will have to wait to see what the OP responds if this works or not for them, and then can troubleshoot further with more details. Until then I found some resources for troubleshooting this issue:

• Fix problems with Xbox Game Bar on Windows
  
• Xbox Game Bar - Cannot Record Video - Microsoft Community
  
• XBox Game Bar Recording Top Left Corner - Microsoft Community
  
• X-Box Gamebar Recording in the Corner with Black border - Microsoft Community
  

Thanks,