csrutil disable
Restart computer
In the terminal, type
sudo open /Applications/TextEdit.app /System/Library/LaunchDaemons/com.apple.ManagedClient.enroll.plist
change
<key>com.apple.ManagedClient.enroll</key>
<true/>
to
<key>com.apple.ManagedClient.enroll</key>
<false/>
So that the changes take effect
@todd-gallant yeah I went to 14.1 and had the issue. Yesterday I was able to get into the OS and play around for hours. The only thing was the notification on the Apple Menu, so thought it would be okay. Today, it was completely locked out.
I followed the steps summarised by @luckydzp here: luckydzp then it started to work.
I feel (though not 100% sure) if you upgrade then after you log in, disconnect any internet connection, then follow the steps, it /should/ work and has for me (so far... but now probably jinxed it)