Q: Blinking pixels on screen after Yosemite install

deltone - I noticed mine most recently in Mail. Not necessarily a wallpaper background.

Me too

Been chatting up some high end engineers, and it had come down to a software glitch.we ran recovery and no pixel issue there, so the tech was pretty sure it was software...my assumption from the start. so, tomorrow we're going to backup and do A clean install. If that doesn't work, I'll go for a hardware fix.

F

I can confirm that a complete wipe of my hard drive and install of Yosemite has fixed my issue.  No graphics issues yet, will continue testing and report back if anything comes up.

Hey Pat...
(and all others who have been on this thread trying to get the wangoo fixed).....

On this thread I didn't see what your display problem was. Is it the blinking pixels we have discussed? I have a senior engineers # and am supposed to call him in the am and we are going to do a backup (probably with CarbonCopyCloner), wipe the disk, and do a clean install. Have you seen any pixel-blinking or other artifacts visible on the reloaded Yosemite? Is 'all still well in paradise?' This engineer gave me a CS code that would allow me to get a graphics card replaced, but after running a 'recovery' there was NO evidence of a hardware problem, so the plan has changed from me going first for a graphics card, to the clean and reinstall. I really would rather have the **** pixel problem fixed than a new graphics card with the same pixel problem. Sound right to you?

Thanks,

Fred

Good to hear Pat, sounds about right considering the troubleshooting we have done here.

IF anyone sees this return after an erase and install, please post back!

Hi all...
Like patscanlon, I had the blinking pixel problem. I finally, with the help of a top-tier tech in Canada, worked for TWO days to get the d/loading, installation and completion achieved. But, at the end of the day, it seems to have worked. Worked last night, and this am it is STILL WORKING (YAAY!)! I have CCC (Carbon Copy Cloner) but the support (Greg) ran me over the hurdles via migration assistant. It went like this: We started by shutting down, restarting while holding Command-r. When the screen came up we erased the disk. (NOTE: We first did a check at time machine and found that a backup had occurred about 1 hour previously). When the erase was complete, we tried to reinstall Snow Leopard (the latest disks I had) but the drive spit them out 4 times, so we figured oh ohhh! If you recall, the way this got started, I tried to burn a cd, and it would act like it was writing, but wouldn't actually burn anything to disk. So, I had just bought a low-cost Samsung optical burner. We tried the disk in that, and bingo-we installed SL. Then came update, update, update. When Snow Leopard was fully updated, we then went to the apple store, and downloaded 10.10. Again, it took hours to get it downloaded and installed, REFUSING to let anything migrate from the old time-machine, or any other source, but just accepting the basic 10.10 installation. After completing that, we opened the "migration assistant", and moved everything except computer and settings to the "new" Mac. (Leaving, hopefully, and corrupt Yosemite remnants behind). After about 4-5 hours of moving files, the computer restarted, and crappola-it was still the beginner Snow Leopard, without any of my apps. So, in the apps folder I found all of my previously used apps that I wanted reintalled. So I started with 'Open Office' and decided that I'll have to 'one at a time' re-install every old program I had been using!!! WRONG! After the install, it showed a screen saying 'you have to restart to finish install. Do you want to restart now?' I hit yes, and after the restart, everything was back to the original state-exactly the way it looked before the pixel problem started to occur. Screen desktop config, list of all my apps, EVERYTHING! AAHHHYUP!

So, at this point, Greg still thinks that I have something questionable with the graphics card, as well as the internal optical drive (superdrive?-remember, it wouldn't open the Snow Leopard disks, but the cheap external Samsung free-standing DVD player did)! So he is calling my closest Mac repair place, telling them what steps he (we) took, and that the dvd drive AND the graphics need to be thoroughly tested, and replaced as indicated. AND, my thirty day support is still clicking down....I should have a little over three weeks left. It looks like, (and I hope) that I fell into the Happy Vat, and will come out with a darn-near refurbed unit. I'll let you know as soon as another applle glitch turns my smile askew.
Until the next time,
F
PS....most of you know, or should, that IF and when you get to an engineer level tech, things get fixed, they don't pass the buck, the really are an invaluable assist in getting back on track. "My" tech gave me his phone number, his email addy, his hours at work, and permission to keep in touch, at LEAST until the 30 day support has ended.

Hi,

My iMac mid 2011, as I thought, had a failing graphics board (forget which board it is attached to) or card, and most likely the card it was attached to is also failing.

I had erased the hard-drive, returned to 7.0, upgraded, put on Yosemity, and it was worse. 

My reason for pixel and freezing certainly will not be the same issue, I believe, for everyone but I am glad I have posted on this subject.

Apple is taking care of my iMac under warranty.

I will post after the iMac is returned and I operate it for a while to see how it does.

Bad news!  After two days same graphics issue has come back up.  No idea now if a complete erase and install does not resolve the problem.

Things that I did trying to solve this issue:

1.- Upgrade from Mavericks to Yosemite on Macintosh HD (1 partition) with download from Apple Store: Display Issues appeared for the first time after 6 hours.

2.- Clean install of Yosemite on Macintosh HD (1 partition) with USB installer and no third party applications installed, only Yosemite: Display Issues appeared for the first time after 45 min.

3.- Clean install of Yosemite on second partition (Yosemite HD partition with 499GB) keeping Macintosh HD partition (499GB) with Mavericks: Display issues appeared with Yosemite after 2 hours. No display issues when boot with Mavericks.

4.- Clean install of Yosemite on second partition (Yosemite HD partition with 499GB) keeping Macintosh HD partition (499GB) with Mavericks and taking out Corsair memory (2 x 4GB) and putting 4 x 2GB Original Apple iMac memory: Display issues appeared with Yosemite after 12 hours. No display issues when boot with Mavericks.

I'm done whit this... Just hopping for Apple to come with a fix in a short time. Running Mavericks in my iMac (mid 2011) and Yosemite in my 13" MacBook Pro Retina (mid 2014)

I know I've been here helping us all isolate this issue, I have further evidence to suggest this is a software issue.

I completely erased my 10.9.5 Mavericks install, installed Yosemite 10.10.  Within the first 12 hours of use I had replicated the issue within Apple Mail.  I'm on a Mid 2012 MacBook Air so this now tells me this is not iMac specific.

The best thing we can all do is report this to AppleCare, use www.apple.com/feedback and document it through a Genius Bar appointment as well if possible.

Please post back with any news.  I have to say this doesn't look like hardware to me.

It can only be software, but has it corrupted the graphics card? I have that Canadian tech set for a chat on Monday am. He previously stated that doing a recovery would show whether or not it was hardware related, but after all the cr appola we have gone through he said that re hardware, the graphics card is about the only hardware that could cause/allow this to happen. I'll post back after I see what comes next. I bet its a trip to a service center, a repair/replace order for the graphics card, as well as the optical DVD/cd drive (remember, yesterday when we tried to boot from TWO different disks, the drive spit them out, time after time. The only saving grace was that I JUST bought a free-standing Samsung optical drive, and via THAT we could start the disk!

I too am having the problem on my i7 iMAC 11,3 model.  What I find interesting is when I go into System Preference, Display, and change from "Best for Display" to "Scaled" and select a different scale then back to the original scale the system goes for hours without the problem.

Heres a query fer ya...
What if I followed the same procedures as before, but with a tilt? (back up all to time machine, wipe the drive, use the disks to reinstall Snow Leopard, then used migration assistant to bring all the data back). Hunh? I must add that I see some backups from earlier date in the time machine folder, but this machine has NOT been set to backup since the (ugly) Yosemite install...

and EVERYONE on this thread, PLEASE go to 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, possibly software and hardware! If enough folks explain the problem, then MAYBE we can get more folks working on the issue, pixelation, and corrupt screen.