MacOS Sierra bricked my iMac

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Level 1

5 points

MacOS Sierra bricked my iMac

So yesterday my 2014 imac prompted me to install MacOS Sierra, which I did, leaving it installing at 5.30 when I left work with approx 33 mins remaining.

I Come into work this morning to be greeted with the following screen:

I've tried turning it off and on and trying to boot in safe mode by holding shift when turning on, but nothing makes a difference, this comes up as soon as I turn it on and nothing makes it go away? It's flickering but not moving and nothing seems to make it respond.

Desperate for any suggestions!

iMac, macOS Sierra (10.12)

Posted on Sep 22, 2016 2:28 AM

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Answer 1

Best reply

LucoBrasi

Level 5

5,702 points

Sep 22, 2016 2:32 AM in response to bryanbenjy

This looks like hardware issue for me. Try to reset SMC settings and NVRAM

Reset the System Management Controller (SMC) on your Mac - Apple Support

How to Reset NVRAM on your Mac - Apple Support

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Answer 2

bryanbenjy Author

Level 1

5 points

Sep 22, 2016 3:01 AM in response to LucoBrasi

ok, so both of those things have now been done. The computer itself is clearly booting up, because this time I could see the cursor was blinking for me to put my password in, which I did and pressed enter. Then I could tell from the colours and flashing that it was loading up my desktop. However it still looks like this so I can't actually do anything or see what to do?

literally sat here unable to work, so Frustrating!

any further ideas anyone?

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Answer 3

Njofrekk

Level 2

198 points

Sep 22, 2016 3:23 AM in response to bryanbenjy

I'm guessing that a bad graphics card driver was installed, but I cannot offer any good advice on what to do but for you to take it to Apple store so they can repair the damage and/or reinstall OS.
Try hooking it up to an additional monitor and see what happens?

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Answer 4

bryanbenjy Author

Level 1

5 points

Sep 22, 2016 3:28 AM in response to Njofrekk

good idea! i had a second monitor connected and it wouldnt load to start with so I disconnected it in case that was causing the problem. Now I've just connected it up again after I've managed to log in and that displays fine, with my iMac screen still having lines all over.

SO should I try installing Sierra again? Can I roll back to El Capitan? What's the best way forward?

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Answer 5

Njofrekk

Level 2

198 points

Sep 22, 2016 3:36 AM in response to bryanbenjy

Well, try reinstalling Sierra, but first back up your data. If the problem persists, then roll back to El Capitan. If the problem is still there, take it to Apple and check with them.

Drop a post here when you fix the issue.

Good luck.

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Answer 6

bryanbenjy Author

Level 1

5 points

Sep 22, 2016 8:27 AM in response to Njofrekk

OK, so I eventually managed to re-download Sierra and reinstall it. Sat here watching to see if there were any clues, but nothing out of the ordinary happened, it installed, restarted and then the lines just didn't go away.

This really is so frustrating. Next step I guess is to re install El Capitan?

but what I don't understand is why this has happened? I have a 2014 iMac, no modifications, always runs fine. I've installed other updates with no problem. But i can't find anyone else having the same problem so it's not a common thing?

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Answer 7

Loner T

Level 9

59,471 points

Sep 22, 2016 8:35 AM in response to bryanbenjy

Can you boot into Safe Mode - Try safe mode if your Mac doesn't finish starting up - Apple Support ?

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Answer 8

bryanbenjy Author

Level 1

5 points

Sep 22, 2016 8:47 AM in response to Loner T

It boots fine, I've got a second monitor connected now and set to mirror so I can use the computer aspect of it on the second mon and the OS itself is working fine, but the display on the imac screen itself just permanantley has these horizontal bars running up and down so I can't see anything on the screen, so presumably it's some sort of driver issue?

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Answer 9

Loner T

Level 9

59,471 points

Sep 22, 2016 8:58 AM in response to bryanbenjy

Can you run Using Apple Hardware Test - Apple Support and check if you see any errors? AHT does not show all errors.

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Answer 10

bryanbenjy Author

Level 1

5 points

Sep 22, 2016 9:11 AM in response to Loner T

JJust trying this, using apple diagnostics, but it would appear that it uses that before it loads the second monitor, so i can't see anything on the screen on my iMac!

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Answer 11

Loner T

Level 9

59,471 points

Sep 22, 2016 9:19 AM in response to bryanbenjy

Disconnect the external monitor.

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Answer 12

bryanbenjy Author

Level 1

5 points

Sep 22, 2016 9:24 AM in response to Loner T

Im not sure how that's going to work?? The whole problem I've got here is that my imac display isn't displaying anything other than flashing lines as per my screenshots above and this whole post??

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Answer 13

Loner T

Level 9

59,471 points

Sep 22, 2016 9:28 AM in response to bryanbenjy

Disconnect the external monitor, reboot the Mac and hold the 'D' key. AHT has minimal GPU requirements.

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Answer 14

bryanbenjy Author

Level 1

5 points

Sep 22, 2016 9:34 AM in response to Loner T

OK just done that and no change. Lines up and down the screen and cant see what it says

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Answer 15

Loner T

Level 9

59,471 points

Sep 22, 2016 10:40 AM in response to bryanbenjy

Using How to install OS X on an external drive connected to your Mac - Apple Support, try to install El Capitan on an external disk and boot from it. Does the display work properly? If it does not, you may want to talk to someone at the nearest Apple Store.

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