Q: Blinking pixels on screen after Yosemite install

Hi,

Took my iMac mid 2011 into an Apple store and it was replaced with a new "late 2013" 21.5 inch  Processor 2.7 GHz  Intel Core i5  8GB  1600 MHz DDR3.

The mid 2011 iMac was non-re-repairable.  

After initial research (which finally led me to make an appointment via Apple Support for the 'genius bar',  I found that the graphics board was failing which is mounted on another card (forgot which card). 

Via 'Macworld' UK I found a statement (date not on printout) that "Apple has begun a graphics card replacement program for select mid-2011 iMac configurations, after determining that the graphics cards in some 2011 iMacs may fail.    ......Apple says that some AMD Radeon HD 6970M video card used in 27in iMacs with 3.1 GHz quad-core Intel i7 processors may fail.

The graphics card failure in these models can cause "the computer's display to appear distorted, white or blue with vertical lines, or to turn back,"  Apple says."

At the Apple 'Genius Station' a deeper test was run then I had seen previously and it supported the fact of 'graphics card' failure.  In upgrading to Yosemite just to see what would happen, I had numerous warnings upon a restart that "A graphics problem has been detected" and I did click report and sent each incident to Apple.

My suggestion....get an appointment at 'genius' or where ever you get service.

Great service by Apple after I chose to take the iMac mid 2011 into the Apple store for my appointment.   I was called 6 days after taking it in and was informed of the internal issues and that I would receive a new Mac.  Fantastic.  iMac was covered by the 'warranty' I was told, 100%.

OK! So heres MY deal!!!
I had mentioned that I had been in contact several times with a senior apple rep in Ontario. Had had given me a CS # that would extend my applecare for thirty days, and cover repairs. My mid-2011 iMac has been in the local Mac shop for 11 days or so, and today I was told it was ready. As stated, the drive would not read any OS X install disk, so I worked it off my freestanding optical drive. Long story short-all of the "fixes" and wipes and Adobe conflicts etc etc that folks (including me) have posted are a bunch of (some, and some not) educated guesses, trying to get a fix or workaround. End of story, Radeon cards are warrantied for FOUR years!!! So, the super (internal) drive was replaced, as was the Radeon 6770 Card. Brought it home, and been up for a while, and its purring like a itten, with no apparent conflicts, no artifacts, just smooth sailing.
I whined and b**ched and finally got a tech who was apparently right-the 10.10 DL somehow affected something in the architecture of the graphics function, damaging the actual card. So, with a new card, and a new drive, I'm keeping my fingers crossed, but I must say, that when you finally get ahold of someone that KNOWS the product, things get much easier. I hope that (1) this puppy keeps on taking a lickin and keeps on tickin, and (2) y'all get some relief SOON. BTW, the local tech AGAIN stated that there is a hot fix called 10.10.1, but that it was not out for consumption yet, whatever that means!
Good luck, and I hope to stay absent for a while!

F

Like I said, as did old toad, on the 'problem with graphics thread, replacing the failing Radeon card seems to work for everyone who had it replaced. All of the other wiping, disabling, transparency might be workarounds, and temp at best. I see one person say they did a wipe and reinstall and EVERYTHINGS FINE! Then they are back in two hours saying that it started again.

Its simple. The Radeon cards are failing, and the way to fix the issue is to have them replaced. FYI...the Radeon cards are supposedly warranted for FOUR years, which makes a 2011 still in the game. Call the apple techs, and work to the top tier. Ask 'em how to get your BAD card replaced.

Also, if you have been seeing my posts, the tech/engineer I finally got hold of (in Ontario, Canada) gave me, and also called the local Mac shop, and gave them a "CS Code" which extended FULLY my applecare policy (which had expired 6 months ago) for thirty days. EVERYTHING was covered-new Radeon card, New internal superdrive, labor. Charge to me was $0.00!

Ok - So after installing Yosemite we also started noticing blinking pixels. Well my 10 yr old was getting so frustrated, because it would also lock up on him and then he would have to restart the computer. Well, yesterday when I got home he told me the fan was on and would not cut off. After a few minutes of him on the mac, he said "Dad the blinking pixel are gone"..... Well, we thought there had been a update. So we started researching how to get the fan off and relized we needed to do a SMC reset. After shutting down the mac unplugging it from the wall waiting 15 seconds then plugging back up waiting 5 seconds and then press power, it started without the fan on. Once it booted up the blinking pixels started instantly!!!!!! So, we researched how to get the fan to turn back on... We held the power button and unplugged the mac from the wall (took a few tries) but then it started with the fan on high!!! That was last night. Since then not one blinking pixel!!!!!! So hopefully others can try this.. Or it can help figure out what is going on.

a client reported that this helped:

Turn Off Transparency:

To turn off the transparency:

1. Under the Apple menu, choose System Preferences
2. Choose Accessibility
3. Choose Display
4. Click the "Reduce Transparency" check box

Transparency OFF did the trick for me.

Running iMac 27 mid 2011 12,2 Radeon 6770M 512

I'm having the same problem. Flashing pink and or green pixels getting increasingly worse over time -- eventually freezing the machine.

Mid 2010 27" iMac just upgraded recently to Yosemite.

ATI Radeon HD 5750 1024 MB

Tried zapping PRAM -- short term relief provided then problem returned.  Turned off transparency (also short term relief then problem re-occurred -- have kept it off ever since but no help)  Tried resetting SMC by unplugging machine -- no change from that (from an above post maybe I should try that multiple times?)

Noticed pattern that when I returned to machine after a while the problem of flashing pixels was worse.  Now I'm trying turning off Energy Saver (both Computer Sleep & Display Sleep set to Never). Also I increased time until screen saver kicked in to one hour.  It's been just over 24 hours including the machine being left on sitting idle over night and not a single flashing pixel.  Hoping this holds me over until aforementioned 10.10.1 with this flashing pixel problem fix is released.

Thanks Pink Panther for the link.  I had hoped the latest update would resolve the issue, but it did not.  I've submitted a bug report and hope everyone will do the same.

Pink Panther wrote:

 

VERY IMPORTANT

All of you, please adopt the excellent advice by deltone, (see above) and please act asap:

 

Go to http://www.apple.com/feedback/, pick iMac, then on the dropdown

choose "BUG" and issue your complaint and description of what Yosemite

has done to your computer.

 

I have already reported, now it is your turn...

Turning off transparency doesn't work for me.

It is a problem with the graphics card. Apple knows about the problem. Apple thinks it knows which iMacs are affected. My machine has the problem. My serial number isn't on Apple's list of bad machines, so they won't replace the card for free. My next step is to bring the machine in to the Apple Store..

How do I turn off transparency ?

Go to: MENU/System Preferences/ Accessibility /Display /Reduce Transparency (check the box)

IT WORKED!!!!!!!! After months of misery, this did work.

Hello, I think I might be having the same issue, however, it's on a 13" MacBook Pro early 2011. As you can see in the link, for me the issue is contained within the application windows and doesn't affect the entire screen (when it does, the menu bar or dialog boxes remain intact). I am also getting blinking pixels when opening PDFs which have been scanned via image capture. It's not really blinking pixels, but more the effect frozen on the entire PDF – the PDF looks scrambled. Reducing transparency doesn't solve the issue. Tried it in Mavericks, and all was fine (the PDF opened without any glitches).

One thing that I did notice, was that I would get the blinking pixels when pushing the GPU with Final Cut or Aperture.

I was close to writing it off as a failure of the integrated graphics, and was ready to replace my Mac; but after reading this, I'm glad I didn't do that just yet.

Thanks a lot for your help in advance.

Scrambled MacBook Pro screen and external display not recognised.

Early 2011 MacBook Pro 13"

2.3GHz i5

16GB RAM

External display: LG EA93

OS X 10.10.3