MacBook not starting up

Hi there

Is your Mac completely restarted, or is it still busy with turning off? If it allready restarted and it boots to this progress circle, see this to see If you can fix this. From this apple support article: If your Mac starts up to an Apple logo or progress bar – Apple Support (UK)

If the startup process never progresses beyond an Apple logo or progress bar:

1. Press and hold the power button on your Mac for up to 10 seconds until your Mac turns off.
2. Every Mac has a power button. On laptops that have Touch ID, press and hold Touch ID.
3. Turn your Mac back on. 
4. If the issue persists, press and hold the power button until your Mac turns off. Then unplug all non-essential accessories from your Mac, including printers, drives and USB hubs. There may be an issue with one or more of these devices or their cables. 
5. Turn your Mac back on.
6. If the issue persists, press and hold the power button again until your Mac turns off. 
7. Repair your startup disk as described in How to repair a Mac disk with Disk Utility.
8. If the issue persists, reinstall macOS from macOS Recovery.

If you need help, contact Apple Support.