My macbook air does nit open. I see a black screen and cursor only.

Welcome to the Apple Support Communities.

Force shut off your Mac by pressing and holding the power button or Touch ID sensor. Then, turn it back on and try again.

If the issue persists, startup into Safe Mode and test: How to use safe mode on your Mac - Apple Support.

Jack

My macbook air will not start up. I have a black screen with only the cursor showing. How can I fix it?