Unable to turn on HDR

I have this as well. Can't enable HDR.

Initially I could enable HDR without issue, but experienced this problem ever since the game crashed on me and I had to check file integrity in Steam. Rebooting didn’t fix it, neither did toggling off and on HDR in Windows.

I was playing around in the graphical settings for other reasons and noticed after the integrity check the game had reset my upscaling technique from DLSS to temporal, so I changed it back to DLSS and HDR could be enabled again. Somehow, at least in my case, it appears temporal upscaling blocks HDR.

Hopefully playing around with the upscaling mode works for other people too. It’s almost certainly a bug as I can’t understand how upscaling technique could interfere with the ability to output HDR, so fingers crossed the developers can sort this out soon.

Turning DLSS on also enabled the option for me.

Same here. Enabled on my monitor but greyed out in-game regardless of any other settings.

Turns out, in my case, HDR was off in windows display settings.

When turned on, the game recognises it on loading and I can change those settings. The HDR option on my monitor isn't available then.

The same thing happened to me on Linux. Testing on my PC and Steam Deck. I was able to use HDR before 1.3.0 update. Now, the option is always greyed out. All other HDR-enabled games like Horizon Zero Dawn detect HDR correctly.

EDIT:

I figured it out. Game only allows HDR when using fullscreen mode. Please change that limitation. We should be able to use HDR regardless of this (windowed, borderless, exclusive)

The HDR is broken, visit my win auto HDR solution, if you want a better HDR