Can’t erase your Mac’s startup disk? Try Internet Recovery as a last resort

You might be trying to erase the recovery partition, which you can’t do. Here’s how to erase the disk.
macos high sierra recovery mode reinstall
Apple
    Related:
  • MacOS
  • Mac
  • Troubleshooting
Glenn Fleishman’s most recent books include Take Control of iOS & iPadOS Privacy and Security, Second Edition (covering iOS 15/iPadOS 15), Take Control of Your M-Series Mac, and Take Control of Securing Your Mac. In his spare time, he makes Tiny Type Museums. He’s a senior contributor to Macworld, where he writes Mac 911.