Black smudge on bottom screen only in locked mode - retina 2014

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Black smudge on bottom screen only in locked mode - retina 2014

Mine is a MacBook Pro (Retina, 15-inch, Mid 2014) 2.2GHz with Integrated display. When I opened the laptop this morning, I was welcomed by a locked screen and noticed a black smudge on the bottom portion of the screen. My heart sunk for a moment but when I logged in, I didn't notice the smudge any longer.

I see the black smudge which looks like an ink blot (see attached picture) when I go back to locked screen again. Is this a failed LCD or could there be something else going on? If it is a failed LCD why don't I see the problem when it is unlocked? How to fix it? Thanks for any help.

Notice the black smudge. The white dot at the bottom left of the screen above is just the hidden cursor.

No smudge when unlocked as can be been above.

MacBook Pro (Retina, 15-inch, Mid 2014), OS X El Capitan (10.11.2)

Posted on Dec 30, 2015 8:26 AM

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Answer 1

steve359

Level 6

17,187 points

Dec 30, 2015 8:29 AM in response to theapplet

Could be a hardware fault. If you bought AppleCare, you have 3 years of hardware warranty and Genius Bar can diagnose it for free repair -- it is repeatable so you can show them.

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Answer 2

theapplet Author

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Dec 30, 2015 9:08 AM in response to steve359

Thanks Steve. It's been an year as of last month since I purchased the mac and I have not opted for any extended warranty or protection plans.

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Answer 3

steve359

Level 6

17,187 points

Dec 30, 2015 9:14 AM in response to theapplet

You can take it in anyway for a free estimate. You can beg and plead to add AppleCare at this point, but do not hold much hope.

Macs are reliable, but sometimes bad parts do get into the bin. Sorry.

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Answer 4

theapplet Author

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Dec 30, 2015 9:14 AM in response to steve359

I didn't know I can get a free estimate. Thanks. I'll try my luck.

Still looking forward to any DIY tips or some help understanding why would LCD behave differently in locked and unlocked mode.

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Answer 5

steve359

Level 6

17,187 points

Dec 30, 2015 9:21 AM in response to theapplet

iFixit.com has repair guides and videos. Much of the work can void warranties, but that is probably not relevant now for you.

Locked mode is displaying mostly dark colors (deep blue, black) which are technically "absence of color". Your second image is of a white background, which is "all colors" and using the backlight. My guess is that the pixel control is much more active on white screens or at least errors are less noticable.

But if others want to trounce my technical analysis as useless, they can override my statements.

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Answer 6

theapplet Author

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Dec 30, 2015 10:01 AM in response to steve359

Appreciate that info. Btw, to show unlocked screen with different backgrounds, here are few more screen shots while playing media.

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Answer 7

theapplet Author

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Dec 30, 2015 11:51 AM in response to theapplet

Ok, here is an update.

I rebooted and ran the diagnostics which indicated there are no problems. So, I restarted but still saw the same black splotches all across the bottom portion. Out of blue, I just thought I'd try changing the desktop background and lo and behold, I didn't see the black smudges anymore. When I switched back to the original background shown below (El Capitan 2), I notice the smudged display again. I don't know why with the original background, the black splotch was not glaringly visible to me all this while until today but seems this definitely has something to do with the transparency of desktop background and locked screen. Anyways, I'll stick to using a different background rather than thinking it is a failed LCD or some other hardware issue. I got a Genius bar appointment to get it checked in any case or may be that isn't needed. In any case, what a relief!!! Thanks for checking.

Best wishes for the New Year you all.

Here is the original background.

Here is the locked screen with the above background.

Here is the locked screen with new background.

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Answer 8

steve359

Level 6

17,187 points

Dec 30, 2015 11:55 AM in response to theapplet

Live and learn -- good detective work. You have learned something I did not consider, gives you something to share with others in the ASC who have the same issue.

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Answer 9

theapplet Author

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Dec 30, 2015 12:13 PM in response to steve359

Thanks Steve. It seems silly now but well sometimes that is how it is. 🙂

Reminds me of this quote by Alfred North Whitehead, a British mathematician - "The silly question is the first intimation of some totally new development."

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