A kernel panic is a computer error that the operating system cannot easily recover from and your computer restarts unexpectedly.
If you are using OpenAFS, you MUST uninstall it prior to upgrading to a new macOS version. If you do not, your computer will end up in a kernel panic loop. If your Mac does end up in a kernel panic, here are the steps you can take to recover from it.
- Shut down your computer.
- On startup, enter single-user mode (Command + S).
- From the command line, type
/sbin/mount -uw /
rm -f -R /var/db/openafs
- The macOS High Sierra installation will continue. After the upgrade is complete download and run the Stanford Software Removal Tool for Mac.
- Remove OpenAFS.
- Reboot your computer.