CEH Said:
"Sonoma restart 'Installer progress': I installed Sonoma and later at restart it hung for a while showing "Installer progress" near the Apple icon. This was before anything else showed in menu bar. Any suggestions? My system is an 2020 Mac Mini M1"
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Troubleshooting a Stalled macOS Upgrade:
Boot in Safe Mode:
Apparently, the macOS is stalled. To, try logging in while in Safe Mode. In Safe Mode, Login Items do not run at login, certain preferences are set aside, and damaged system files are then reset. So, once logged in to Safe Mode, wait 30 seconds, and then restart your Mac, seeing if you can log in go here: How to Use Safe Mode on your Mac - Apple Support