Summary

Lightroom is unable to activate HDR editing on my external HDR10 monitor.

When HDR is disabled in macOS, Lightroom correctly displays the yellow warning icon indicating that HDR is unavailable. After enabling HDR in macOS, the yellow warning disappears, indicating that Lightroom detects HDR support.

However, the HDR status indicator remains red and Lightroom reports that "the operating system or display has HDR disabled." As a result, HDR editing cannot be enabled on the external display.

HDR editing works correctly on the built-in MacBook Pro XDR display.

Steps to reproduce

1. Connect an LG 27US550-W HDR10 monitor to the MacBook Pro.

2. Enable HDR for the external display in macOS Display Settings.

3. Launch Lightroom.

4. Open a supported HDR image.

5. Attempt to enable HDR editing.

Expected result

Lightroom should recognize the external display as HDR-capable and enable HDR editing, just as it does on the built-in MacBook Pro display.

Actual result

The HDR indicator remains red and Lightroom reports that HDR is not enabled for the operating system or display, preventing HDR editing on the external monitor.

System

• Adobe Lightroom 9.4 (Apple Silicon)

• macOS 26.5.1

• MacBook Pro (M1 Max, 32 GB RAM)

• External display: LG 27US550-W (HDR10)

• Connection: USB-C → DisplayPort (issue also reproduced through a Thunderbolt 4 dock)

Troubleshooting performed

I performed the following checks to rule out configuration or hardware issues:

• Verified HDR is enabled in macOS.

• Confirmed that the warning icon in Lightroom disappears after enabling HDR in macOS, indicating Lightroom detects HDR support at some level.

• Tested both through a Thunderbolt 4 dock and with a direct USB-C → DisplayPort connection.

• Restarted Lightroom after enabling HDR.

• Verified GPU acceleration is enabled and Metal is functioning correctly.

• Reproduced the issue consistently.

Additional diagnostics

To verify the monitor's HDR configuration independently, I checked the display using BetterDisplay.

BetterDisplay reports:

• HDR enabled (Native)

• HDR10 (PQ)

• 10-bit RGB output

• Current timing supports HDR

• Current scaling supports HDR

• DisplayPort connection

• P3 color gamut

Cross-application comparison

To verify that the issue is specific to Lightroom, I tested the same monitor with other HDR-capable applications.

Results:

• Apple Photos correctly displays HDR photos on the external monitor.

• Photomator correctly displays and edits HDR photos on the same monitor.

• Lightroom correctly enables HDR editing on the built-in MacBook Pro XDR display.

Because HDR functions correctly in other applications using the same display, macOS configuration, and hardware connection, the issue appears to be specific to Lightroom's detection or initialization of HDR on this external display.