Fix 0x000005B5: Invalid Monitor Handle

When This Error Shows Up

You're plugging in a second monitor via HDMI or DVI, or maybe you just woke your PC from sleep. Instead of a second screen, you get a popup with error 0x000005B5: ERROR_INVALID_MONITOR_HANDLE. This usually happens right after a Windows update, a GPU driver update (NVIDIA or AMD), or swapping monitors between different ports. I've seen it on Windows 10 build 22H2 and Windows 11 23H2, especially with older Dell U2412M or Samsung SyncMaster monitors.

What's Actually Going Wrong

The monitor handle is a pointer Windows uses to talk to your display. When it's invalid, Windows lost the connection between the driver and the monitor's EDID data — that's the little block of info that tells your PC the monitor's resolution, refresh rate, and supported modes. The root cause is usually a stale EDID cached in the registry or a corrupted display driver state. It's not a hardware problem 90% of the time, so don't order a new monitor yet.

Fix It in 3 Steps

Step 1: Clear the Stale EDID Cache

This is the real fix. Windows stores EDID data under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\DISPLAY. When you swap monitors or cables, the cache gets confused.

Press Win + R, type regedit, hit Enter. Say Yes to the UAC prompt.
Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\DISPLAY.
Expand each monitor GUID (they look like MON1234). Under each, you'll see folders named by connection type like 5&3b1c2a8&0&UID43520.
Right-click each subfolder and choose Delete. Do this for all monitor entries. Yes, it looks scary — I promise it's safe. Windows rebuilds these on next boot.
Close regedit and restart your PC.

Step 2: Reinstall the Display Driver

Sometimes the driver itself has a bad handle reference. Skip Windows Update here — go straight to the source.

Press Win + X and select Device Manager.
Expand Display adapters. Right-click your GPU (e.g., NVIDIA GeForce RTX 3060) and choose Uninstall device.
In the dialog that pops up, check the box that says Delete the driver software for this device. This clears the stale cache.
Click Uninstall. Then restart your PC.
Windows will install a basic driver on reboot. It might look ugly for a minute — that's fine.
Download the latest driver from NVIDIA.com, AMD.com, or Intel.com for your GPU model. Don't use the generic Microsoft driver.
Install the fresh driver and reboot again.

Step 3: Check the Monitor Cable and Port

If steps 1 and 2 didn't work, test the physical connection. I know it's annoying, but I've seen a frayed HDMI cable cause this exact error.

Try a different cable — HDMI 2.0 or DisplayPort 1.4, depending on your monitor.
Plug the monitor into a different port on your GPU. Avoid the motherboard ports if you have a dedicated GPU.
Test with another monitor if you can. If the error moves to the second monitor, the cable or port is the culprit.

What to Check If It Still Fails

Let's say you've cleared the registry, reinstalled the driver, and swapped cables — and the error still shows up. Then try this:

Disable Fast Startup: Go to Control Panel > Power Options > Choose what the power buttons do > Change settings that are currently unavailable. Uncheck Turn on fast startup. Reboot. Fast startup caches old display data and can resurrect this error.
Change the Scaling Mode in GPU Control Panel: In NVIDIA Control Panel, go to Display > Adjust desktop size and position. Set scaling to No scaling and apply. For AMD, it's under Display > Scaling Mode > set to Center or Full panel.
Run SFC and DISM: Open Command Prompt as admin. Type sfc /scannow. Then DISM /Online /Cleanup-Image /RestoreHealth. This fixes system file corruption that might mess with monitor handshakes.

I've had this error twice on a Dell XPS 15 with a USB-C to HDMI dongle. The registry trick was all it needed. If you're on a laptop with a dock, also try disconnecting the dock and plugging the monitor directly into the laptop's HDMI port — docks add another layer of confusion.