I have encountered this somewhat lately. I have all the updates on my iMac, and I'm pretty tight on security. My hard drive crashed in June, and I had to replace it. My iMac is 4 years old this month. Otherwise, everything seems okay. Could this be warning signs of things to come? Any ideas?
iMac, macOS High Sierra (10.13.1), null
To make sure I understand, by "abstract," do you mean that there is an actual abstract-like image (think van Gogh's The Starry Night) or that the screen looks like confetti or some other bizarre set of colors and lines? Does this issue also occur when first starting up the iMac?
I'm betting on the latter. If so, then it may be possible that your iMac's graphics is having an issue synchronizing to the built-in screen. One test would be to temporarily connect a second monitor to your iMac and see if the issue occurs on that device upon waking up the iMac.
I don't think so, but I would suggest that you check your iMac for any presence of adware by using a program, like Malwarebytes for Mac to see if anything shows up. In addition, or alternatively, you can also use EtreCheck for this ... and to determine the overall "health" of your desktop.
I downloaded and ran Malwarebytes and EtreCheck and found no problems. By the way, I just have this one iMac along with several iPads and iPhones. Is the free version of Malwarebytes okay, or do I need the premium since I just have one computer? I really appreciate your advice.
The free version should be fine. Between the two, I was hoping it might have "caught something." But the good news is that the issue is not malware-related.
I suggest that you temporarily remove any wallpaper Desktop images and disable the screen saver. Set the "Turn display off after" to 1 minute and allow the iMac to enter sleep mode to see if this "abstract" image reappears after waking the system.
You were correct in your reference to van Gogh. This does not occur when first starting up the iMac. It only happens when waking it up from sleep mode. Do you think this is anything serious?
Mine is bright and abstract...nothing real fancy.
I shut down my iMac about eight hours ago, and the problem has not appeared again since I rebooted it. We'll see what happens. I'll keep you posted and try your suggestion if it happens again.
After you have used Malwarebytes and EtreCheck, is it okay to keep them on your iMac and run them from time to time?
What could it mean, when your iMac wakes up from sleep mode, and you have an abstract desktop picture that you did not set?
