Thin white lines appearing on iMac screen

No, not in that screenshot.

Screenshots are generated by the GPU and will not show screen defects.

To show screen defects, you need to take a photo with an iPhone or digital camera and then post that image.

Also please make sure that there are no names or other personal information in any of the images that you post on line.

Yes now I see the lines in the display panel.

Sadly replacing the display panel at this point, will cost more than the 2017 21.5" iMac is worth.

Long story short. I switched to Mac mini's and external displays back in 2010 after having an iMac display issue.

see > Mac mini - Apple

and > Mac - Which Mac is best for me? - Apple

plus > Connect a display to Mac mini - Apple Support

Hard to say. Take a screenshot and a picture with a phone or camera, then post those using the Image Insertion tool.

Not surprising for an all-in-one computer after 8 years. Unfortunately they will continue to worsen over time.

Old Toad wrote:

Are the lines horizontal or vertical? I see two faint vertical lines in the screenshot I'm replying to.

Is your iMac an M1 model?

Hi OT

The computer information was edited out by a mod...?

The OP has a 2017 21.5" iMac running macOS 13.7.6 Ventura.

They are vertical.

I can see 4 lines (1 is fainter) and a couple of wide less pronounced bands.

Are the lines horizontal or vertical? I see two faint vertical lines in the screenshot I'm replying to.

Is your iMac an M1 model?

Your eyes are much better than mine. I have big problems with contrast. The white background does me in so I use the Dark Mode.

I could see only two at the left of center.

If it doesn't affect the author's workflow he should just try to ignore it and begin saving up for a new Mini M4 with a 3rd party 27" 4K monitor. I got a 32" monitor so I could run at lower resolution without sacrificing much screen real estate. What I got was $650 less than what a similarly configured new 24" iMac would cost.

Note: after opening up that screenshot in Photoshop Elements and enhancing the contrast I could see all 4 lines.

Old Toad wrote:

Your eyes are much better than mine. I have big problems with contrast. The white background does me in so I use the Dark Mode.

I could see only two at the left of center.

I never worn prescription glasses, but needed Cataract surgery a few years back. It was amazing what new eye lenses can do when that's the only issue.

If it doesn't affect the author's workflow he should just try to ignore it and begin saving up for a new Mini M4 with a 3rd party 27" 4K monitor. I got a 32" monitor so I could run at lower resolution without sacrificing much screen real estate. What I got was $650 less than what a similarly configured new 24" iMac would cost.

+1 agreed.

Note: after opening up that screenshot in Photoshop Elements and enhancing the contrast I could see all 4 lines.

👍