If your Mac starts up to a circle with a line through it - Apple

A circle with a line through it means that your startup disk contains a Mac operating system, but it's not a macOS that your Mac can use. 

My startup screen is a circle with a slas… - Apple Community

Startup issue. PLEASE HELP - Apple Community

If your Mac starts up to a circle with a line through it

MacBook Pro suddenly stopped working, the technician says the

Cannot boot iMac (late2015) - Apple Community

I accidentally reset my MacBook Pro witho… - Apple Community

Apple locked my Mac Pro

MacBook Air - Apple Community

Crossed out circle at boot up. Recovery n… - Apple Community

MacBook Pro suddenly stopped working, the technician says the

Mac OS install on AMD Ryzen (VMWare) Opencore

Mac Mini won't restart after Mail crashed… - Apple Community

Mac OS install on AMD Ryzen (VMWare) Opencore

Mac OS install on AMD Ryzen (VMWare) Opencore

Mac Basic Startup Troubleshooting Steps - Apple Community