Monitor flickers or goes black after sleep mode? Here's the fix

Quick check (30 seconds): Cable and power

Before you dive into settings, the most common cause is a loose cable or a monitor that's not getting consistent power. Here's what to do:

1. Turn off your monitor and computer. Unplug the monitor's power cord from the wall or power strip.
2. Unplug the video cable (HDMI, DisplayPort, or USB-C) from both the monitor and your computer.
3. Check both ends of the cable for bent pins or debris in the connector. If you see bent pins, you need a new cable—no fix for that.
4. Plug the power cord back in firmly. Then plug the video cable in at both ends, making sure it clicks or seats all the way.
5. Turn on the monitor first, then the computer.

Now test it. Put your computer to sleep (Windows key + X, then U, then S). Wait 30 seconds, then wake it up. If the flickering's gone, you're done. But if it still acts up, move to the next step.

Moderate fix (5 minutes): Disable fast startup and update GPU driver

Windows 10 and 11 have a feature called 'fast startup' that sometimes messes with the display driver when waking from sleep. This is a known issue on systems with NVIDIA and AMD cards. Let's turn it off.

1. Open the Control Panel. Type 'Control Panel' in the Start menu search.
2. Click 'Power Options'.
3. On the left, click 'Choose what the power buttons do'.
4. At the top, click 'Change settings that are currently unavailable'. You'll see a shield icon next to it.
5. Scroll down to 'Shutdown settings'. Uncheck the box next to 'Turn on fast startup (recommended)'. It's recommended by Microsoft—they're wrong for this scenario.
6. Click 'Save changes'.

Now update your GPU driver. Don't rely on Windows Update for this—go straight to the source.

• NVIDIA: Go to NVIDIA's driver download page, pick your card, download the latest Game Ready or Studio driver, and install it. Choose 'Custom (Advanced)' install, then check 'Perform a clean installation' to wipe old settings.
• AMD: Go to AMD's driver page, select your product, and get the latest Adrenalin driver. During install, choose 'Factory Reset' if it offers it.
• Intel: Use the Intel Driver & Support Assistant from their site—it's easier than hunting for the right one.

After the driver install, restart your PC. Then test sleep again. If it still flickers, the problem is deeper.

Advanced fix (15+ minutes): EDID override or replace the monitor's firmware

If the flickering persists, the monitor itself might be sending wrong EDID (Extended Display Identification Data) data to your GPU after sleep. This is a handshake issue—the monitor says it can handle a resolution or refresh rate, but when it wakes up, it can't. I've seen this with older Dell Ultrasharps and some Acer Predator models.

You have two options here. Try the cheaper one first.

Option 1: Force a lower refresh rate or resolution in Windows

1. Right-click on your desktop and select 'Display settings'.
2. Scroll down to 'Advanced display settings'.
3. Under 'Refresh rate', drop it down one step. If you're at 144 Hz, try 120 Hz. If at 60 Hz, try 59 Hz (it's a common alternate).
4. Under 'Display resolution', drop it one step if that doesn't help.

Test sleep again. If it works, you can live with the lower setting or try the next option.

Option 2: Override the EDID using CRU (Custom Resolution Utility)

This is a free tool that lets you bypass the monitor's EDID. Download CRU from MonitorTests.com. It's safe—I've used it for years.

1. Run 'CRU.exe' as administrator.
2. At the top, you'll see your monitor model listed. Click it.
3. Under 'Detailed resolutions', select the highest resolution and refresh rate you're using (likely 1920x1080 at 60 Hz or 144 Hz). Click 'Delete'.
4. Now click 'Add'. In the window that pops up, set your resolution and a refresh rate that's 1 Hz lower than what it was. So if it was 60 Hz, set it to 59 Hz. If 144 Hz, set it to 143 Hz.
5. Click 'OK' to close all windows.
6. Run 'restart64.exe' (or 'restart.exe' on 32-bit systems) from the CRU folder. Your screen will flicker once—that's normal.

Now test sleep again. If the flickering stops, you've fixed it. If not, you might need to delete the highest resolution entirely and create a slightly lower one—like going from 1920x1080 to 1920x1080 at 59 Hz, or even 1366x768 temporarily to see if it holds.

If nothing works: Replace the monitor's firmware (manufacturer only)

Some monitors—especially BenQ and ViewSonic—have firmware updates available on their support sites. Check your model's support page. If they have a firmware updater, it's worth trying. But in my experience, if the EDID override fails and the firmware update isn't available, you're looking at a hardware fault in the monitor's power regulation circuit. It's time to replace the monitor or use a display port-to-HDMI adapter as a last resort (sometimes the adapter changes the handshake).

One last thing: if your monitor has a 'Deep Sleep' or 'Power Saving' feature in its on-screen display menu, turn it off. It's often buried in 'Settings' > 'Power' or 'ECO Mode'. That alone fixes flickering for some LG and Samsung monitors.

Real-world trigger: This exact problem shows up most often with dual-monitor setups where one monitor is on DisplayPort and the other on HDMI. The GPU gets confused about which port to wake first. If you're running two monitors, try swapping them to the same cable type—both HDMI or both DisplayPort—if you can.