I have the same issue going on with my 2013 iMac, whose display has passed on. I was using an old Apple display as a 2nd screen but not set up as the log-in screen. I did a bunch of things suggested here and elsewhere, and even saw that there is a shortcut for forcing the displays to mirror. I didn’t try that because I have more computers in my office so I tried connecting to the dead-display iMac via screen sharing. Voila! The login screen came up on that computer. I was able to log in, went to preferences/displays/mirror displays. Now I am able to work on this computer again, albeit with a single display.
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I have the same issue going on with my 2013 iMac, whose display has passed on. I was using an old Apple display as a 2nd screen but not set up as the log-in screen. I did a bunch of things suggested here and elsewhere, and even saw that there is a shortcut for forcing the displays to mirror : Cmd+F1 (or Fn+Cmd+F1 (though I haven’t tried this). Instead, I tried connecting to the dead-display iMac via screen sharing. Voila! The login screen came up on that computer. I was able to log in, went to preferences/displays/mirror displays. Now I am able to work on this computer again, albeit with a single display.
I have the same issue going on with my 2013 iMac, whose display has passed on. I was using an old Apple display as a 2nd screen but not set up as the log-in screen. I did a bunch of things suggested here and elsewhere, and even saw that there is a shortcut for forcing the displays to mirror. I didn’t try that because I have more computers in my office so I tried connecting to the dead-display iMac via screen sharing. Voila! The login screen came up on that computer. I was able to log in, went to preferences/displays/mirror displays. Now I am able to work on this computer again, albeit with a single display.