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.
macOS High Sierra (10.13)
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.
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.
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.
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.
Thanks for your reply !
I have an "old" iMac late 2010. It still works perfectly, though.
The strange thing is that with some application, there is no issue. For example, when I'm in full view with VMWare (running a Windows instance), there is absolutely no problem.
I'll try the transparency trick.
Thanks again!
You're welcome!
Did it start before or after you upgraded to High Sierra...?
If it started after upgrading, try downloading and reinstalling High Sierra again.
If it started before upgrading, then it could just be "old age" starting to take it's toll on the graphic's chip.
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?
I'm going to say both. The hardware is getting weaker with age and the software (Sierra and High Sierra) is more demanding.
strange colored squares in the screen
