GPU artifacts appear on photo

The two possibilities that come immediately mind is that you've got an older Intel Mac with buggy Apple/AMD drivers or you've got an intermittent hardware problem (e.g. memory or disk). Both of these can produce the artifacts in your screen shot.

Building on Axel's suggestions, do the LR menu command Help > System Info and copy/paste the entire contents here so we can see exactly which versions of hardware and software LR thinks you're running and important LR options that are set.

You can quickly determine if it's a buggy Mac graphics driver by setting Preferences > Performance > Use Graphics Processor to Off.

It seems there are an incompatibility with your graphic card and/or driver, or the driver is faulty.

Try is to switch off the GPU support from the Lightroom preferences and check if that helps to fix the issue.

Go to Lightroom > Preferences > Performance tab > Uncheck "Use Graphics Processor" > Restart Lightroom.

https://helpx.adobe.com/lightroom-classic/kb/troubleshoot-gpu.html

If it's help see here Troubleshoot GPU issues | Lightroom Classic (adobe.com) and check the different steps.

Another step is to try to reset the Lightroom preferences.

https://www.lightroomqueen.com/how-do-i-reset-lightrooms-preferences/

It's recommended to backup your preferences before you reset the preferences to the default settings:

https://helpx.adobe.com/lightroom-classic/kb/preference-file-and-other-file-locations.html

Check if your system is up-to-date. Do you have installed all recent updates and patches for the operating system and the device drivers, especially the graphic driver? If you have a NVidia graphic card installed, make sure that you are using the recent Studio version of the driver, not the Game Ready version.

Please provide a copy of your 'System Info'. This can be get from the LrC Help > System Info menu item. There's a copy button in the System Info dialog. Press this button and paste the info into your next forum post.

in the future, to find the best place to post your message, use the list here, https://community.adobe.com/

p.s. i don't think the adobe website, and forums in particular, are easy to navigate, so don't spend a lot of time searching that forum list. do your best and we'll move the post (like this one has already been moved) if it helps you get responses.

<"moved from cc desktop bugs">