P: Colored "pixel" artifacts/subdued blacks in shadow areas (older Macs) (also visible on CR)

I'm starting to look for alternatives now. I would hope there will be a significant rebate on what we are paying while this is going on

Don't downgrade the OS.  Only one of the Apple M3 MBPs ever shipped with Ventura (specifically, 13.5, not an earlier version of macOS 13).  Our IT department once put their standard image on my new MBP, only it was an older version of OS X than the system initially shipped with and some things didn't work, performance was bad and it crashed a lot due to missing drivers or other incompatibilities.

@tdoggett, xactly the same situation for me. I have an iMac 27" late 2015, which is great to work with. Now we are getting the message that the computer is too old and the graphics card manufacturers are no longer updating drivers. On the other hand, I'm currently planning to buy a new Macbook Pro M3 so that I can work properly again. However, Adobe support still advises not to run Creative Cloud on Sonoma / OS14. What does this mean? I should downgrade the M3 computer to OS 13? Considering the prices Adobe is charging monthly, the product quality is downright ridiculous, not to mention outrageous. If anyone has an alternative suggestion to Lightroom - please post.

At this point, your best bet is to go back to Lr Class 12.3 because it seems to be the last version without this impairment.  Some people have found that disabling GPU support also works, but apparently export ignores this setting and still uses GPU and thus can remain impaired.

If your catalogue has been upgraded and won't go back, save you metadata and re-import your images.  This will preserve some/most of your edits, but if you've used newer features from 12.4, 12.5 or 13.0, such Process Version 6 instead of Process Version 5 or lens blur or newer camera/lens support, these will be lost.  Hopefully many edits will survice.  You will also lose other things such as collections because these exist only in the catalogue.

What is the latest from Adobe on this?

I'm seriously considering jumping to C1 before I update a 2015 Mac PRO. It's $7k to get a new one.

Adobe, we need your help on this!

UGH. that machine is not that old. 

Now that we hear this, there is no excuse that it's only OLDER macs with outdated graphic cards!

Adobe, PLEASE HELP!!!!!!

We can't do our jobs!!!!

Mac Pro 2013 - I also have this problem. Colorful artifacts in the shadows. During preview and on exported images.

My 2015 27" I-Mac runs perfectly - EXCEPT for this LR issue which makes editing impossible. I have been waiting for a fix. I hate to buy an entirely new machine for what seems to be a programming bug.

I have a problem with the pictures, namely it shows me yellow or cyan colored pixels in the deep tones in developing mode and also as JPEG after export.
Does anybode know why this happens?

Can you get Version 4 to synch or copy to each image aka lock in Version 4??

I can synch everything else.  I check of Calibration when synching.  It still reverts every image to Version 6 and I have to go in and chancge it to Version 4 on EVERY image!  ANd if i decide I want to make any other lats changes and have set to Verion $, it goes back to 6 and have to go reset to 4 again.  SO FRUSTRATING!!!!