I accidentally deleted my fingerprint and now I can't add it back. each time I try to add my fingerprint it says it has to turn off auto logon and then the add fingerprint button disappears.
Have you checked Apple menu > System Settings (or System Preferences) > Users & Groups to see if Automatically login is off?
Sorry, I don't know why that would happen. If you haven't already, rebooting is worth a try and then you may want to contact Apple Support. There is a Get Support link at the top right of this page.
Yes and when I do that then the touch id icon disappears from system preferences. So I am caught in an endless circle if I turn on auto logon then the icon reappears but I can't add a fingerprint.
iMac Touch ID
