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strange colored squares in the screen

Hi everyone, it has been a couple of weeks now since I have these strange colored squares that appear and flash on my iMac. I did a full NVRAM and SMC reset but the problem comes back. See the example in the attached image.


It seems that the problem comes more often when I open an app for the first time, especially Safari.


Anyone has ever seen something similar? I really don't know what to do...

Thanks!


Mathieu.User uploaded file

macOS High Sierra (10.13)

Posted on Oct 3, 2017 4:48 PM

Reply
Question marked as Top-ranking reply

Posted on Oct 3, 2017 5:46 PM

Looks like a graphics issue.


What year model is your iMac...?

see > Identify your iMac - Apple Support


In addition to what you have already tried,

1. Try it in Safe Mode, as per > Use safe mode to isolate issues with your Mac - Apple Support

2. Try going to: Apple > System Preferences > Accessibility > Display and checking Reduce Transparency.


User uploaded file


If neither of those help...?


Make an appointment with your local Apple Authorized Service Provider for an evaluation.

To find an AASP, go to > https://locate.apple.com/ and click on Service.

5 replies
Question marked as Top-ranking reply

Oct 3, 2017 5:46 PM in response to mathieufromlevis

Looks like a graphics issue.


What year model is your iMac...?

see > Identify your iMac - Apple Support


In addition to what you have already tried,

1. Try it in Safe Mode, as per > Use safe mode to isolate issues with your Mac - Apple Support

2. Try going to: Apple > System Preferences > Accessibility > Display and checking Reduce Transparency.


User uploaded file


If neither of those help...?


Make an appointment with your local Apple Authorized Service Provider for an evaluation.

To find an AASP, go to > https://locate.apple.com/ and click on Service.

Oct 3, 2017 7:03 PM in response to den.thed

It started before upgrading go High Sierra. In fact, I as hoping that it would fix the issue 🙂


But why does it seem to be related to the software I'm using? I mean... I just shut my VM Ware (which I was using full screen, without any issue) and when I'm back on my iMac desktop... no colored squares... everything works fine...


So it is hardware or software?

strange colored squares in the screen

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