black screen before login retina mbp

Is anybody has fixed the problem at home? I have tried all the ways to fix it but nothing happened. It seems that problem with BootRom or EFI, but can't find how to check/verify them. Is it possible to check the logs of starting system before logo?

Hello everyone,

I have two iMacs (late 2013) 27" with 32gb RAM, and 3TB Fusion drive. Both are running on latest Sierra 10.12.5. They both perform great, fast, and reliable since I bought them in December 2013. I've been very good at updating them whenever there is available update. Only about 2 weeks ago, I noticed that one of them, when I press the power button on the back, the screen would light up (black) and would get stuck there for about 15 seconds before the fan would start up and the startup chime would play, and the Apple logo would come up, then it would take about another 15 seconds (which is normal) to reach the desktop screen. At first, I thought that was strange that there's a delay in hearing the chime when it used to be almost instantaneously after pressing the power button. What's baffles me is that the other iMac with same specs and OSX installed is not having this issue.

What I did so far which made no difference:

1. Select Startup disk and restart

2. SMC reset

3. PRAM reset

4. Swapped RAMs with the other iMac

5. Safe mode

6. Diagnostic Tools reported no issues found

7. Check potency of the internal battery (turned off wifi, unplugged iMac for 3 days, plugged it back, turned on) it kept date/time which means the battery is in good shape.

This is very frustrating! Any suggestions would be very much appreciated. Please HELP. Thanks!

Hello there Edward,

Thank you for using Apple Support Communities!

I think next it would be a good idea to try resetting the PRAM and performing a safeboot:

About NVRAM and PRAM

http://support.apple.com/kb/HT1379

Resetting NVRAM / PRAM

1. Shut down your Mac.
2. Locate the following keys on the keyboard: Command (⌘), Option, P, and R. You will need to hold these keys down simultaneously in step 4.
3. Turn on the computer.
4. Press and hold the Command-Option-P-R keys before the gray screen appears.
5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6. Release the keys.

After resetting NVRAM or PRAM, you may need to reconfigure your settings for speaker volume, screen resolution, startup disk selection, and time zone information. If issues persist, your Mac's logic board battery (not a portable Mac's rechargeable battery) may need to be replaced. The logic board battery helps retain NVRAM/PRAM settings when your computer is shut down. You can take your Mac to a Mac Genius or Apple Authorized Service Provider to replace the battery on the logic board.

And

To start up into Safe Mode (to Safe Boot), do this:

1. Be sure your Mac is shut down.
2. Press the power button.
3. Immediately after you hear the startup tone, hold the Shift key. The Shift key should be held as soon as possible after the startup tone, but not before the tone.
4. Release the Shift key when you see the gray Apple icon and the progress indicator (looks like a spinning gear).

During startup in Mac OS X v10.4 through Mac OS X v10.6.8, you will see "Safe Boot" on the login window, which appears even if you normally log in automatically. During startup in Mac OS X v10.2 through v10.3.9, you will see "Safe Boot" on the Mac OS X startup screen.

To leave Safe Mode, restart the computer normally, without holding any keys during startup.

From: Mac OS X: Starting up in Safe Mode

http://support.apple.com/kb/HT1455

Cheers,

Sterling

Edward-

Any luck getting this issue cleared up?

Were they really certain that it was a hardware problem, or did they just choose this method to try and remedy the problem? I have had the exact same problem with my Macbook Pro 15 Retina only after upgrading to Mavericks. Prior to this new installation, when the Macbook restarted, there was no black screen. This indicates that it was a software problem, not hardware.

I have an appointment with the Genius Bar on Monday to see what they think. Hopefully they do not suggest a logic board replacement, as I am beyond my one year warranty.

Hi Edward.

hi, have exact the same problem. since a few months. after searching i found your post with the same thing. Q: did they replace anything else like your screen?? luckely i have a 3 years warranty, but the company i bought it ( mactrade.de ) trys to tell me now, that i need to exchange the screen, but this is (very strangly!) somehow not included in the warranty and they want me to pay for a new screen!! unbelievable, because i told them that all others with same problem never exchanged the screen, only the logic board.

so be carefully where to buy your mac ;-)...and how they handle so called "warranty". at mactrade.de it was my last mac i bought!

Hello,

I have the same problem after upgrading to El Capitan, how did you solve it?
Regards