How do I turn my Mac on
My Mac is not booting. A circle with a line passing through shows
MacBook Pro 13″, macOS 10.13
Question marked as
Best reply
You might have to reinstall macOS, check the steps in this article to use Disk Utility to check your drive for possible errors and let it fix those:
...
A prohibitory symbol, which looks like a circle with a line or slash through it, means that your startup disk contains a Mac operating system, but it's not a version or build of macOS that your Mac can use.
- Press and hold the power button on your Mac for up to 10 seconds, until your Mac turns off.
- Use Disk Utility to repair your startup disk.
- If Disk Utility found no errors or repaired all errors, reinstall macOS.
- If you still need help, please contact Apple Support.
...
copied from: If your Mac starts up to a circle with a line through it - Apple Support