Something strange going on with my iMac; it's hard to describe.

When I click on any link on my Reading List sidebar, for a split second there is a flickering line which goes across the screen. When I say line, what I mean is, a faint copy of the link below flickers for a split second horizontally across part of the screen.

It only happens on Safari (11.1). No other app, so it must be a problem with Safari only. I have macOS 10.13.4 installed. I have tried resetting Safari, resetting SMC and NVRAM and even deleting the plist file from my Library folder and repairing my disk in Disk Utility......

A short video showing my problem can be viewed here, about 2 seconds into the video......


Anybody have this and found a solution?

1 Answer 1


It's more of an annoyance (bug) in Safari than an actual problem because it doesn't cause anything to fail. It's also definitely not something that can be fixed by resetting NVRAM, the SMC or performing First Aid on your disk(s).

What you are seeing is a dialog box that pops up; usually when you are hovering over a link. I extracted the frame from your YouTube video clip to see what was being shown and it appears to be the link below the one you have selected.

Safari YouTube video of pop up error

As you have already said, the problem only manifests in Safari. Your best course of action would be to provide feedback to Apple so that they can address the issue/bug. Provide them with a link to this question/answer so they get the full picture (no pun intended).

Bottom line: It's nothing more than a box with a document title/link in it and it only appears for less than a split second. Annoying? Perhaps. Problematic? Not so much.

  • 1
    Thank you very much for your helpful reply, Allan. You are correct in that this an annoyance and not a problem with my iMac (I hope). I've provided to feedback to Apple (thanks for the link) and hope that they resolve this in a future update. I was about to do a "clean install" but when I saw your reply, I've decided to wait to see what happens. So you think this is just a bug in Safari and not a problem with my machine as it only appears in Safari? I have an etrecheck report if that would help? Thanks again.
    – Wilky76
    May 1, 2018 at 2:52
  • I don't believe it's a system wide issue necessitating a full reinstall. If you're seeing the issue in other Apple apps (like Mail, Messages, Photos, iTunes, etc.) then it may be system wide.
    – Allan
    May 1, 2018 at 3:27
  • Thanks Allan. Yes, this definitely only happens in Safari and only when I click on a link in my reading list as shown in the video. There is no other way of replicating the problem. Also, I've noted that the dialogue that pops up always pops up in the same location on the screen. That's why I initially thought this could be a display or GPU problem.
    – Wilky76
    May 1, 2018 at 7:11
  • A quick update. I recently bought a new MacBook and I've just entered my iCloud details and while using Safari, I am experiencing the same issue with flickering horizontal lines. So it's not my iMac that has the problem. It must be iCloud related.....
    – Wilky76
    Jul 27, 2018 at 7:51

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