You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Headhunter06 Author

Level 1

44 points

On boot, iMac Apple logo blinks red after update to Mac OS Sierra

After upgrading to MacOS Sierra, my 2015 iMac 21.5 Retina has a blinking red Apple logo and then a brief splash of screen flicker when booting. Once booted, the computer seems to run fine, with no obvious flakiness. I'm not sure why the logo blinks red and then the screen flickers -- bad drivers; a software fault in the boot phase; some issue with the fusion drive; or perhaps some other gremlin? A quick internet search reveals that at least a few others have the same issue with this OS version, and it seems to have happened in years past with other MacOS version upgrades. But there are no good answers on how to fix it. I've rebooted several times hoping it would clear itself, but no luck.

iMac, macOS Sierra (10.12), iMac 2015 21.5 4k Retina

Posted on Sep 22, 2016 7:48 PM

Top-ranking reply

Yoann Denis

Level 1

13 points

Posted on Nov 2, 2016 7:45 AM

Hello,

I installed Sierra 10.12.1 yesterday and I have the same issue on my iMac 4K 2015 with 2TO Fusion Drive.

I don’t think it’s a hardware problem because I re-installed El Capatin and no issue.

I hope Apple will fix this issue in sierra, for me I’ll wait longtime before to install Sierra again.

View in context

74 replies

phranky

Level 2

310 points

Nov 26, 2016 7:33 PM in response to Headhunter06

So now I know I'm not the only one. As there seems to be no definitive answer, I think I'll just buy some Apple Care and sit back.

Bummer!

Csound1

Level 9

60,033 points

Nov 26, 2016 7:37 PM in response to Community User

You had this problem ?

Csound1

Level 9

60,033 points

Nov 29, 2016 10:04 AM in response to Paul6778

Apple Techs do not read these forums. If you want to tell them use this link

Roth91

Level 1

54 points

Nov 29, 2016 2:45 PM in response to Paul6778

It doesn't reinstall anything on your computer. It just reinstalls the operating system. Just "set it and forget it". Run out to see Star Wars and come back to a new computer

Nov 29, 2016 3:28 PM in response to Roth91

I reinstalled Sierra a few times and it didn't change anything.

Paul6778

Level 1

8 points

Nov 30, 2016 4:42 AM in response to Roth91

I know Roth91 was just commenting to the person whom when talking to Apple was saying that it could be a logic board problem, which I don't believe at all.