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How Do I Determine Which Monitor Used By High Sierra During Startup?

What determines the monitor used to display the Apple logo, etc., at power on?

I have a second monitor with its display rotated 90° to a vertical orientation. That monitor displays the first steps of power on instead of on the main monitor after my upgrade to 10.12.3.

Screen arrangement is correct and the menubar is located on the main monitor in display preferences, so everything straightens out when booting is finally complete. It is just annoying to have to login sideways on the second monitor.

How can I change it back to screens appearing on the main monitor during the initial power on?


Comments: 2 Responses to “How Do I Determine Which Monitor Used By High Sierra During Startup?”

    2 years ago

    I know what you mean as I also have a second (and third) screen that is rotated 90 degrees. When I restart, one of those vertical screens usually does get the startup progress bar. I’ve never been able to figure out why the Mac chooses that one, other than it is definitely quicker to power on than the “main” horizontal screen. So maybe that’s all it is — whichever one responds to the system first.

    However, it has never been an issue for me as all three screens are going by the time I need to log on, and the main horizontal one is the one that shows the login prompt. Is that happening for you?

    Also, I rarely, if ever, do a “startup.” I always sleep my Mac and it only restarts if an update requires it. The only time I did a shut down and start up in the last few years is when I had to unplug my Mac to switch to a new UPS. Are you shutting your Mac down? If so, why?

    2 years ago

    Thanks for your comments Gary. I don’t feel alone with this one!

    In my case, it seems that the DisplayPort monitor does respond before the HDMI one. But the login prompt does remain at 90 degrees there.

    I also avoid total shutdowns, although there have been several “restart” requirements lately with upgrades.

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