MacBook Air keyboard repeats letters when typing

You can try cleaning the keyboard by following the instructions in the following Apple article:

How to clean the keyboard of your MacBook or MacBook Pro - Apple Support

If you still encounter this problem, then try using an external keyboard to see if that works properly. If an external keyboard works fine, then you have a hardware issue with the built-in keyboard which will require it to be replaced with a repair by Apple or an AASP.

Try opening System Settings > Keyboard.

At the top is the setting for "Key repeat rate." Adjust the slider for a slower repeat rate and see if that helps.

Thank you for reaching out. 😉

First, let’s see if this issue happens in Safe Mode:

1. Shut down your Mac.
2. Press and hold the power button on your Mac. As you continue to hold the power button, your Mac turns on and loads startup options. When you see Options, release the power button.
3. Select your startup disk. It's named Macintosh HD, unless you changed its name.
4. Press and hold the Shift key, then click the “Continue in Safe Mode” button below your startup disk.
5. Log in to your Mac. You might be asked to log in again.

If the strange behaviors do not occur, then it may possibly be a software issue.

If the issue doesn't continue in safe mode:

Leave safe mode by restarting your Mac normally, then try to reproduce the issue.

If the issue doesn't return, it might have been resolved by the other things that safe mode did at startup, such as checking your disk and clearing caches.

If the problem persists, then let’s try this:

• Software Update.
• Use Apple Diagnostics to test your Mac.

If none of those ideas work, then I recommend service.

Service Checklist:

• Mac service pricing.
• Check AppleCare Coverage.
• Get your Mac ready for service.

Click ▶︎ Start a Service Request. ⚛️

Need more help?

• United States: 1-800-APLCARE.
• Contact Support.
• Mac Support.
• Mac User Guide.

Click ▶︎ Check Repair Status. 🔧

Good luck! 👋🏼😉

Smiliñ 😎 Brian