New macOS Catalina 10.15.7 update fixes 27-inch iMac graphical corruption issue

An update to macOS Catalina incorporates bug fixes for some users, but perhaps more importantly resolves an issue that manifested in graphical issues on the 27-inch 2020 iMac.

The graphical issue was reported around August 31, and accounts of issues first started popping up on Apple's support forums. There was little consistency between trouble reports, and the problem didn't seem to manifest just during intense workloads, and even appeared when the impacted iMac was idle.

Not every user saw the issue, but the problems were mostly focused on the iMac with a 3.6GHz 10-core Core i9 processor, 32GB of memory, and AMD Radeon Pro 5700 XT 16GB graphics. AppleInsider was not able to reproduce the issue.

The update also includes some fixes issued with an interim supplemental update for Catalina, published for select machines earlier in September.

The update is available in combination versions from any Catalina version, and "delta" updates through Software Update for 10.15.6 users. It arrives in conjunction with security updates for macOS High Sierra.

9 Comments

22july2013 3722 comments · 11 Years

About 4 years ago

Apple's exact words were "Addresses a graphic issue that may occur on iMac (Retina 5K, 27-inch, 2020) with Radeon Pro 5700 XT". It sounds like they are claiming this is a 100% reliable fix.

Mike Wuerthele 6901 comments · 8 Years

22july2013 said:

Apple's exact words were "Addresses a graphic issue that may occur on iMac (Retina 5K, 27-inch, 2020) with Radeon Pro 5700 XT". It sounds like they are claiming this is a 100% reliable fix.

I'm sure the fix is reliable. The problem itself wasn't universal, which is wacky.

sflocal 6133 comments · 16 Years

Mike Wuerthele said:

22july2013 said:

Apple's exact words were "Addresses a graphic issue that may occur on iMac (Retina 5K, 27-inch, 2020) with Radeon Pro 5700 XT". It sounds like they are claiming this is a 100% reliable fix.

I'm sure the fix is reliable. The problem itself wasn't universal, which is wacky.

I thought the same thing. It should be happening to every one, so that it's not makes me wonder what's going on.

My 2020 iMac just arrived a couple days ago and I've been hammering the machine non-stop to make sure there's no issues, and I've been keeping an eye out for that graphic "glitch" as well and nothing yet.

A graphics glitch that I did find is that I've been playing "Shadow of the Tomb Raider" and the cloud/smoke effects behave like lightning/strobe-lights. My 2015 iMac does not do this. I'm not reading into it yet and it may be completely unrelated but I'm looking forward to seeing what this OS patch does.

So far... loving my new iMac. I went all-out on it and got the 10-core i9/5700XT/128GB/8TB SSD so I expect this machine to last me a LONG time, and hopefully when it's time to retire it, Apple will have their ARM Macs fully-baked by then.

sunman42 294 comments · 12 Years

Mike Wuerthele said:

22july2013 said:

Apple's exact words were "Addresses a graphic issue that may occur on iMac (Retina 5K, 27-inch, 2020) with Radeon Pro 5700 XT". It sounds like they are claiming this is a 100% reliable fix.

I'm sure the fix is reliable. The problem itself wasn't universal, which is wacky.

Or maybe not so wacky? The 2011 iMac graphics issue only applied to 27-inch models with serial numbers within certain ranges, which to me suggests bad lot(s) of chips or other components.

It'll be interesting to see if the "graphic issue" (singular) applies to the horizontal lines, faint, square corners on windows, and streaking character descenders, or a subset of those.

verne arase 479 comments · 11 Years

Huh.

The only graphical issue I've experienced is that occasionally (after some kind of update), the Mac will boot into a lower resolution placed in the upper left side of the screen.