Mac not starting up
Unrecoverable Error
I am repeatedly getting this error message, after I restarted my MacBook.
”SecurityAgent was unable to create requested mechanism MKAuthPlugin:prelogin.”
MacBook Pro 13", macOS 10.15
If you are using any utterly worthless non-Apple "anti-virus" product, don't: Unrecoverable error securityAgent was unable to create requested mechanism MKAuthPlugin:prelogin.
In that case I surmise the "Bitdefender" product appears to have removed it, rendering the Mac unbootable. That's just one of many possible causes since any similarly categorized non-Apple "anti-virus" product could be responsible.
The ideal solution would be to restore a Time Machine backup. If you have no Time Machine or equivalent backup, then reinstall macOS and uninstall "Bitdefender" or whatever it was that damaged your Mac.
Then (obviously) start using Time Machine.
Read Question: Q: Unrecoverable error securityAgent was unable to ... for a report substantially identical to yours. See if you can start your Mac in "Safe Mode" in accordance with that Discussion.