My Mac book pro has a prohibitory symbol and nothing on support page will work
I cannot get prohibitory symbol off of Mac book pro
If you followed all of these steps
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.
Please follow the last step and contact Apple support to set your Mac up for service