There are a few reasons why your Windows Alt R keyboard shortcut may not be working:

• Xbox Game Bar is disabled. The Windows Alt R keyboard shortcut is used to start and stop screen recording using the Xbox Game Bar. If the Xbox Game Bar is disabled, the keyboard shortcut will not work. To check if the Xbox Game Bar is enabled, open the Settings app and go to Gaming > Xbox Game Bar. Make sure that the Record game clips, screenshots, and broadcast using Game bar toggle is turned on.
• The keyboard shortcut is bound to another program. It is possible that the Windows Alt R keyboard shortcut has been bound to another program. To check this, open the Settings app and go to Time & Language > Language > Input methods > Advanced keyboard settings. Click the Change keyboard shortcuts button and look for the Record game clip keyboard shortcut. If it is bound to another program, you can change it back to the Windows Alt R keyboard shortcut.
• Your keyboard is not working properly. If you have tried all of the above and the Windows Alt R keyboard shortcut is still not working, it is possible that your keyboard is not working properly. Try testing the keyboard in other programs to see if it is working properly. If it is not, you may need to clean or replace the keyboard.

If you are still having trouble getting the Windows Alt R keyboard shortcut to work, you can try the following:

• Restart your computer. Restarting your computer can often fix minor software glitches.
• Update your graphics drivers. Outdated graphics drivers can sometimes cause problems with the Xbox Game Bar. To update your graphics drivers, visit the website of your graphics card manufacturer and download the latest drivers for your graphics card.
• Reset the Xbox Game Bar. To reset the Xbox Game Bar, open the Settings app and go to Gaming > Xbox Game Bar. Click the Fix now button.