Some 24-inch M1 iMac owners have reported an issue with horizontal lines appearing on their screens. The lines look like there is something wrong with the display, but there’s no clear answer as to why this is happening.
There have been complaints surfacing across various online platforms, including Apple Support Community,Reddit, and iFixit Answers. The problem apparently starts after 18 to 24 months of using the iMac. The issue with this is that it’s long past Apple’s standard one-year warranty period. This means Apple can deny free service unless the buyer also has extended AppleCare+ coverage. There have been many users who’ve needed to pay a fee for the service, but it’s been reported that some others have gotten the service for free as an exemption from Apple. There’s no guarantee of getting an exemption, but circumstances could always vary, and that could cause an exemption to be warranted.
Some iMac owners seem to report that the top-right corner of the iMac becomes unusually hot before the lines appear. Unfortunately, that’s not much to go off of, and the lines aren’t exclusive to that part of the iMac. The complaints have been an issue for two years now. Since the time period is pretty common, it wouldn’t be unreasonable to assume that this is a hardware problem exclusive to the 2021 M1 iMac model. No similar widespread complaints are being reported about the newer M3 iMac model, so it may be an issue for this model specifically.
Unfortunately, there’s no way of knowing the reasoning for this particular issue. While Apple has offered some programs to fix common issues with other devices, there is no program for this particular issue. However, if the problem continues to become common and more users report it, we may see that change, but it’s up to Apple to decide.
Source: MacRumors