MacBook Air won’t restart after Monterrey upgrade. Black screen.

Hi there Dfgkkjejsjsjsjzjsis,

Welcome to Apple Support Communities. We understand you have an issue with your MacBook Air not powering on at all. Let's start with steps from this helpful article: If your Mac doesn't turn on

1. Check power connections

Make sure that your power cable is undamaged and plugged securely into your Mac and a working electrical outlet.

If your Mac has no built-in display, make sure that your external display is connected to power, connected to your Mac, and turned on.

2. Press and hold the power button

Press and hold the power button on your Mac for about 10 seconds. (Every Mac has a power button. On laptop computers that have Touch ID, press and hold Touch ID.)

Then press and release the power button normally.

3. Unplug accessories

You could have an issue with one or more accessories or their cables. Unplug all accessories from your Mac, including printers, drives, USB hubs, and mobile devices. Then repeat step 2, above.

4. If you see something on your screen

If your screen shows a flashing question mark, circle with a line through it, or anything else, your Mac is turned on but isn't starting up:

If your Mac turns on but doesn't start up all the way

5. If you see nothing on your screen

If your Mac seems to be turned on but the screen remains blank, the issue could be software related:

If your Mac starts up to a blank screen

6. Reset the SMC (Intel-based Mac only)

If you're using an older, Intel-based Mac, resetting the SMC might help:

Reset the SMC

7. Contact us

If your Mac still doesn't turn on, contact Apple Support.

Reply back with any additional concerns or questions.

Best regards.