ERROR_GRAPHICS_INVALID_GAMMA_RAMP (0xC0262347) Fix

You're staring at a crash dialog or a dead app that just tried to adjust your screen colors. ERROR_GRAPHICS_INVALID_GAMMA_RAMP (0xC0262347). This isn't a random Windows bug. It means the OS graphics subsystem looked at the 256-entry color table an app handed it and said no.

What's actually happening here is that Windows expects a gamma ramp to be a specific shape: three arrays (red, green, blue) of exactly 256 WORD values each, and every value has to make sense for the current display mode. If any of that is off, or if the display driver refuses to accept the ramp at all, you get 0xC0262347. Common triggers: f.lux or Windows Night Light running at the same time as a game's calibration tool, an old version of DisplayCAL writing a ramp a modern WDDM driver rejects, or a GPU driver that crashed and left the gamma table in a bad state.

Work through these in order. Stop as soon as the error goes away.

Fix 1 — The 30-second fix: kick the overlays out

Nine times out of ten the gamma ramp is already owned by another process. Windows only lets one app set the system gamma at a time, and when two try, the second one gets 0xC0262347.

1. Right-click the system tray and exit f.lux, Windows Night Light (Settings → System → Display → Night light → Off), Iris, and anything NVIDIA/AMD color tool that's running.
2. Also close MSI Afterburner and RivaTuner Statistics Server if they're open. RTSS hooks the display pipeline and can reject gamma writes from other apps.
3. Relaunch the app that threw the error.

If it works now, the real fix is to stop both apps from fighting. In f.lux, set it to "Software" mode instead of "Hardware," or exclude the game/app by name. Night Light and f.lux both write gamma ramps, and Windows has no arbitration between them.

Fix 2 — The 5-minute fix: reset the ramp and clean the driver state

If overlays weren't the problem, the current ramp is probably corrupted. A crashed GPU driver is the usual culprit — the DWM compositor restarted but never restored a valid gamma table, so every subsequent SetDeviceGammaRamp call fails validation.

Force Windows to rebuild the ramp:

1. Press Win + Ctrl + Shift + B. This restarts the graphics stack without a reboot. The screen goes black for a second and you hear a beep. That's normal.
2. Open Settings → System → Display → Advanced display and toggle HDR off, then back on if you use it. HDR mode uses a different color pipeline and a stale SDR gamma ramp will fail validation against it.
3. Open Color Management (search "color management" in Start), go to the Advanced tab, and click Change system defaults. Under the Advanced tab there, click Reload current calibrations.

The reason step 1 works when nothing else does: it tears down and rebuilds the display miniport, which reinitializes the gamma lookup table to the driver default. Anything holding a bad handle gets dropped.

If the error comes back as soon as you launch a specific app, that app is the one writing a malformed ramp. Check its settings for a "gamma" or "color calibration" toggle and disable it.

Fix 3 — The 15-minute fix: DDU and clean driver reinstall

Persistent 0xC0262347 across multiple apps almost always means the display driver itself is damaged. Windows Update's driver rollback doesn't fix this because the registry entries for the color pipeline survive the rollback.

Do a proper clean reinstall with DDU:

1. Download Display Driver Uninstaller (DDU) from Guru3D and the latest driver from NVIDIA, AMD, or Intel's site. Don't rely on GeForce Experience or Adrenalin to fetch it — get the offline installer.
2. Disconnect from the internet. Windows Update will try to shove a driver back in mid-cleanup and wreck the process.
3. Boot into Safe Mode (hold Shift while clicking Restart, then Troubleshoot → Advanced → Startup Settings → 4).
4. Run DDU, choose Clean and restart for your GPU vendor. Let it reboot.
5. Install the driver you downloaded. Reboot again before connecting to the internet.

After the reinstall, check the display color pipeline is sane:

Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ICM\ProfileAssociations"

If you see multiple .icm/.icc profile entries pointing at the same monitor, Windows is trying to apply more than one calibration and the ramp write is failing validation. Delete the stale entries or use Color Management to remove the duplicate profiles for that display.

If the error is coming from a specific app, not Windows itself

Apps that call SetDeviceGammaRamp (older games, emulators, some capture tools) can pass a ramp that's technically valid but outside the range the driver accepts. WDDM drivers since Windows 10 1903 are stricter about this than the old XPDM ones were. The app is the problem, not Windows.

• Run the app in compatibility mode for Windows 7 or 8 (right-click → Properties → Compatibility).
• Disable fullscreen optimizations in the same dialog.
• If the app has a config file with gamma settings, cap the value at 1.0 and test. Values above ~1.5 or below ~0.5 frequently fail the driver's sanity check.

If none of that helps and the app is old and unmaintained, you're done. There's no registry key that loosens Windows's gamma ramp validation — that check is in the D3D runtime, not a policy you can toggle. The workaround is to run the app windowed, or accept the default colors.

Quick reference