A quick search found a lot of people are seeing this, and a few suggestions that it’s not worth worrying about on a Mac that’s not using a battery. But my wife thinks it coincides with her Facebook games lagging and pixelating, and now she’s seeing it with her Yahoo mail and a few other websites.
And Safari’s about the only app she runs on this 8GB 27" iMac that’s just 18 months old. I use a 2013 iMac running Safari, Lightroom, Photoshop, Ulysses, Omnifocus, Omnioutliner, BusyCal, Keyboard Maestro, Alfred, etc, and I’ve NEVER seen a message like this. But then I don’t use Facebook often, and don’t run Flash…
Ideas? She thinks it must be something I did to her Mac and I should be able to fix it.