after cold boot of macos, I need manually switch national keyboard to prefered US keyboard

Hello hiaer_silvanna,

Thanks for the additional information regarding the default keyboard on your MacBook Air after a restart.

Next, we suggest restarting your Mac in safe mode. This helps to perform a basic check of your startup disk, deletes some system caches, and more. Here's an article with more information and the proper steps to take: 

• How to use safe mode on your Mac 

Once you're in safe mode, test to see if the issue occurs there. That will tell you more about the issue and help rule out some possible causes. After testing, please restart your Mac as normal and see if you continue to experience the same behavior.

Cheers!

Good afternoon hiaer_silvanna,

Welcome to the Apple Support Communities!

We understand you would like to use a preferred US keyboard when starting your MacBook Air.

• Were you able to do this before updating to macOS 16.4?
• What is the language and default national keyboard you are seeing at the login screen?
• Are you using the keyboard on your MacBook Air, or have you tried connecting an external keyboard?

Take a look at the settings available in the macOS User Guide:

Change Keyboard settings on Mac

Take care.