Blank screen after upgrading Mac Mini to macOS Sierra 10.12.4

Somebody please help 😕! After updating my Mac Mini (Late 2014) and restarting, it seems to be booting up (I can hear the startup tone) but the two screens I have connected remain blank/off in power save mode - not even a flicker.

I have tried one screen at a time, swapping the screens around, swapping the DisplayPort adapters around... and it just does not make any difference - I turn the mini on, I get the startup tone, and... nothing! The screen stays off as if it is not plugged into anything.

I am really pulling my hair out... there isn't even an error to report or something to clickety-click on. Is anyone experiencing this problem? Has anyone managed to solve this problem or found a solution somewhere online?

PS. Both screens and adapters seem to work perfectly when I plug them into my MacBook Air (Mid 2012), which I have yet to update to 10.12.4.

Posted on Mar 30, 2017 7:15 AM

25 replies

Apr 16, 2017 2:26 PM in response to James Ladd1

I wound up connecting both a VGA to Mini Display Port cable and a DVI to Mini Display Port cable to my monitor and plugged BOTH into the Thunderbolt inputs on my Late 2014 Mac Mini. Upon startup, everything booted normally - Apple appeared as well as the progress bar. But it is strange to have to have two video cables connected to have everything boot up normally.

Apr 8, 2017 11:16 AM in response to chartolman

d0nk3y

Level 1

14 points

Apr 10, 2017 1:51 PM in response to Flytrap21

FYI - I just downloaded the Combo update package and updated manually - no problem this time.

https://support.apple.com/kb/DL1910?locale=en_US

BDAqua

Level 10

250,253 points

Apr 8, 2017 10:25 AM in response to Flytrap21

Thanks for the report! 🙂

Apr 12, 2017 8:48 AM in response to Flytrap21

I have experienced this same issue with my Acer monitor remaining blank since updating my mini to 12.4. Turning my monitor's power off and turning it back on always brings the screen back up.

Apr 12, 2017 8:49 AM in response to Douglas76G

I'll try that. Thanks!

d0nk3y

Level 1

14 points

Apr 16, 2017 3:04 PM in response to James Ladd1

Have had this problem with two late 2014 Mac minis at work now. Fixed both by installing the combo update manually (after restoring back to a 10.12.3 restore point with Time Machine).

Apr 16, 2017 3:20 PM in response to d0nk3y

I had updated using the combo update in the first place. I'm waiting for Apple to come out with a patch at this point.

d0nk3y

Level 1

14 points

Apr 16, 2017 3:59 PM in response to James Ladd1

Huh - fair enough! 🙂

Apr 18, 2017 8:47 AM in response to d0nk3y

Perhaps running the combo updater a second time would solve the problem...?

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Blank screen after upgrading Mac Mini to macOS Sierra 10.12.4