If you bought an Apple iMac with the original M1 chip a couple of years back, a new problem that's reared its head with these all-in-one PCs may be some cause for concern.

In the case of this Redditor, the lines cover more than half of the screen - yikes (Image Credit: mnlghtk_ on Reddit)

There are a growing number of reports on Apple's support forum from owners of iMacs that are around the two-year-old mark - and out of warranty - suddenly developing a serious issue with the screen (mind you, some of the reported problems are occuring with machines that are newer).

This manifests itself in the form of a bunch of thin, black horizontal lines across a section of the display which is every bit as awful as it sounds in terms of pretty much ruining the desktop experience. In some reported cases, the black lines are obscuring more than half of the screen.

Tom's Hardware spotted the thread on Apple's forum, which began a long time ago - a year back, in fact, in October 2023, and since then, other affected users have been chiming in and expressing their displeasure, as you might imagine.

The common factors seem to be these lines appearing, then maybe disappearing for a bit, before becoming a seemingly permanent blot on the screen, after the iMac M1 is around two years old as mentioned. iMac owners also report the screen getting very hot in certain parts of the top of the display, and there's some theorizing that the issue might happen to those who run their screen on higher levels of brightness.

This isn't an issue Apple has officially recognized or commented on, and so far, those who've encountered the problem and contacted support have been advised that their screen needs replacing.

There are multiple reports from affected iMac owners on Reddit, too, some of which are pointing out the various threads on Apple's support forum. Collectively, there seems to be some hope that as the volume of complaints grows, maybe Apple will start to investigate what's going on here, and perhaps formulate an official response, or even a replacement program.

The trouble with having a repair performed on an affected iMac is that this raises another issue - the cost of a new screen is something like $700. And there's no guarantee that there isn't something in the Mac itself potentially causing the issue, so it might just happen again to the replacement screen a year down the line - or that'd certainly be our fear anyway.

Meaning that the safest course of action could be simply buying a new iMac - where at least you get full warranty coverage again - or maybe an iMac M1 refurb, which might not be much more than that $700 outlay.