NAch update auf LR 12.4 (MAc, OS 11.7.6)

The first thing that you should 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 Lightroom doesn't start correctly the please see "Solution 2" in the document behind the link below. 

Troubleshoot GPU issues | Lightroom Classic (adobe.com) 

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 

If this doesn't help we need more informations about your environment. 

Which operating system do you use? 

Which version of Lightroom do you use? 

Please post the exact version and not only phrases as "recent", "latest" and so on. 

Please provide also 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.