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.
Cannot boot iMac (late2015) - Apple Community
Mac Basic Startup Troubleshooting Steps - Apple Community
Mac Basic Startup Troubleshooting Steps - Apple Community
My iMac doesn't start and shows a blocked… - Apple Community
MacBook Pro suddenly stopped working, the technician says the
If your Mac starts up to a circle with a line through it
My startup screen is a circle with a slas… - Apple Community
My computer is completely damaged - Apple Community
Mac shutting down for no reason, and unab… - Apple Community
Mc book pro 12 - Apple Community
Late 2010 Air Not Able To Connect To Reco… - Apple Community
Mac Basic Startup Troubleshooting Steps - Apple Community
