Hi @Jacques Chombart, Thank you for reaching out! I'm sorry to hear about your issue. Areas of the image highlighted in red are HDR pixels that your monitor cannot currently display.
Could you please share more information, such as your system information from Help> System Info> Copy and paste it into a text file, and attach it to your response? Is your monitor capable of displaying HDR content? When did you start noticing this issue? Was it after a hardware change, an update to the Lightroom application, or the OS?
While we wait, you can try out the steps below, see if they fix the issue.
1) Enable HDR in your OS.
For Win 11
- Right-click on your desktop and select Display settings.
- Select your HDR-capable monitor at the top.
- Toggle on Use HDR.
For Win 10
- Right-click on your desktop and select Display settings.
- Click on Windows HD Color settings.
- Toggle on Use HDR.
2) In Lightroom, go to Edit > Preferences (on Windows) or Lightroom Classic > Settings (on macOS).
Go to the Performance tab, under Camera Raw, and make sure Use Graphics Processor is set to Auto. After making changes, restart Lightroom.
For more information on working with HDR and its optimization. Please check out this Helpx Article: HDR Optimization
Let us know how it goes!
Cheers!