What causes screen glitches

Screen glitches usually come from one of three places: your graphics card (the hardware that draws images), the driver software that tells your card what to do, or a loose cable between your monitor and computer. Less often, the monitor itself is failing. The good news is that most glitches are fixable without replacing anything—they're usually a software hiccup or a connection problem.

A graphics driver is the software bridge between your operating system and your graphics card. When it's outdated, corrupted, or conflicting with another program, your screen can flicker, show artifacts (strange lines or blocks), freeze momentarily, or display colors incorrectly. On Windows, this is often the first thing to check. On Mac, driver issues are less common because Apple controls both hardware and software, but they still happen.

Physical connections matter too. If the cable connecting your monitor to your computer is loose, damaged, or plugged into the wrong port, you'll see flickering, black screens, or a "no signal" message. This is especially common with older cables or after moving equipment.

Key Takeaways

  • Most screen glitches come from outdated graphics drivers, loose cables, or monitor settings—not hardware failure.
  • On Windows, updating your graphics driver through Device Manager or the manufacturer's website often stops flickering and artifacts when ready.
  • Check that your monitor cable is fully seated at both ends and plugged into the correct port on your computer.
  • If glitches happen only in one program, the problem is usually that program's settings or a conflict with your driver, not your monitor.
  • Overheating graphics hardware can cause glitches; make sure your computer's fans are running and vents are not blocked.

Update your graphics driver on Windows

The fastest fix on Windows is to update your graphics driver. Open the Start menu, type "Device Manager," and press Enter. Look for "Display adapters" and click the arrow to expand it. You'll see your graphics card listed—it might say NVIDIA, AMD, Intel, or another manufacturer.

Right-click on your graphics card and select "Update driver." Choose "Search automatically for updated driver software." Windows will check online and install any newer version. Restart your computer when prompted. If that doesn't work, visit the manufacturer's website directly: NVIDIA.com, AMD.com, or Intel.com. read the latest driver for your exact graphics card model and Windows version, then run the installer.

If you're not sure which graphics card you have, right-click on your desktop and look for an option like "NVIDIA Control Panel" or "AMD Radeon Settings." That tells you the manufacturer. Alternatively, open Device Manager again, right-click your graphics card, select "Properties," and check the "Driver" tab for the driver version and date.

Check your monitor cable and ports

Turn off your computer and monitor. Locate the cable running from the back of your monitor to the back of your computer. It's usually a thick cable with metal connectors on each end. Unplug it from both ends, inspect it for visible damage (kinks, crushed areas, exposed wires), and plug it back in firmly. You should hear or feel a small click when it seats properly.

Pay attention to which port on your computer you're using. Most computers have multiple video ports: HDMI (rectangular, flat), DisplayPort (smaller, rectangular with a notch), DVI (rectangular with two rows of pins), or VGA (blue, with three rows of holes). If your monitor cable is plugged into the wrong port, you'll see no signal or constant glitching. Check your monitor's manual or the label on the back of your computer to confirm you're using the right one.

If you have a laptop, the cable connects to a port on the side. Make sure it's not loose and that nothing is blocking the connection. Dust or debris in the port can cause poor contact; if you suspect this, use a flashlight to look inside and gently clean it with compressed air if you have it.

Adjust refresh rate and resolution settings

Sometimes glitches happen because your monitor's refresh rate or resolution is set incorrectly. On Windows, right-click on your desktop and select "Display settings." Scroll down to "Advanced display settings." Look for "Refresh rate" and make sure it matches what your monitor supports. Most modern monitors run at 60 Hz; if yours is set to 50 Hz or 75 Hz, try changing it back to 60 Hz and restarting.

Also check the resolution. It should match your monitor's native resolution—usually 1920 × 1080 for a standard monitor, or higher for larger or newer screens. If the resolution is too high or too low, your screen may look stretched, blurry, or glitchy. Set it to the recommended option (usually marked as such in the dropdown) and explore the change.

On Mac, go to System Preferences (or System Settings on newer versions), click "Displays," and check the resolution. Mac usually handles this automatically, but if you've connected an external monitor, you may need to adjust it manually. Look for a "Scaled" option and select the resolution that looks sharpest.

Test in Safe Mode to isolate the problem

If glitches happen randomly or you're not sure what's causing them, restart your computer in Safe Mode. This loads only essential drivers and services, which helps you figure out whether a third-party program or driver is the culprit.

On Windows 10 or 11, hold the Shift key, click the Start menu, select "Power," and click "Restart." Your computer will restart and show a menu. Select "Troubleshoot," then "Advanced options," then "Startup Settings." Click "Restart" again, and when the menu appears, press 4 or F4 to enter Safe Mode. If the glitches stop, a program or driver you installed is likely the cause. Uninstall recent software or driver updates one at a time until the glitches return, then remove the problematic one.

On Mac, restart and when ready hold the Shift key until you see the login screen. This is Safe Mode. If glitches disappear, restart normally and check for software updates or uninstall recently added programs.

Check for overheating and hardware problems

Graphics hardware that overheats can cause glitches, flickering, or sudden shutdowns. Make sure your computer's vents are not blocked by dust, papers, or other objects. If you have a desktop, open the side panel (after shutting down and unplugging it) and look for dust buildup on the graphics card and fans. Use compressed air to gently blow dust away from the card and heatsink.

Listen to your computer's fans while it's running. They should be audible but not roaring. If fans are very loud or barely running, your computer may be overheating. Laptops are especially prone to this. Make sure you're using your laptop on a hard, flat surface—not on a bed or pillow, which blocks airflow. Consider using a laptop cooling pad if glitches happen during heavy use like gaming or video editing.

If glitches happen only when you're running demanding programs (games, video editing software, 3D applications), overheating is a likely cause. Restart your computer, close unnecessary programs, and try again. If the problem persists, your graphics card may be failing and you should contact a repair technician.

When to contact a professional

If you've updated your driver, checked your cables, adjusted your settings, and tested in Safe Mode but glitches continue, the problem may be hardware failure. A failing graphics card, monitor, or motherboard component requires professional diagnosis and repair. Contact a local computer repair shop or the manufacturer of your computer if it's still under warranty.

If your computer is a laptop and glitches started after physical damage (a drop, spill, or impact), do not attempt further troubleshooting—take it to a repair technician when ready. Liquid damage or internal component failure can worsen if you keep using the machine.

Frequently Asked Questions

Why does my screen flicker only in one program?

That program likely has a graphics setting that conflicts with your driver or monitor. Open the program's settings and look for options like "V-Sync," "frame rate cap," or "graphics quality." Try disabling V-Sync or lowering the graphics quality. If the flicker stops, you've found the cause. You can also try updating the program itself.

My monitor shows "no signal" but my computer is on. What do I do?

First, check that the monitor cable is fully plugged in at both ends and that your computer is plugged into the correct video port. If you have multiple ports, try a different one. If you're using a docking station or adapter, remove it and plug the cable directly into your computer. If nothing works, the cable may be damaged and needs replacement.

Can a virus cause screen glitches?

Rarely. Viruses usually affect performance, storage, or privacy, not your display. Screen glitches are almost always driver, cable, or hardware issues. That said, if you suspect malware, run a full scan with Windows Defender (built into Windows) or a reputable antivirus program. Malware can slow your system enough to cause stuttering that looks like glitches.

Is it safe to use my computer if the screen is glitching?

Yes, unless the glitches are accompanied by overheating, loud fan noise, or sudden shutdowns. Those signs mean your hardware is in distress. If the screen just flickers or shows artifacts but your computer runs normally, you can keep using it while you troubleshoot. Back up important files in case the problem worsens.

Why did my screen start glitching after a Windows update?

Windows updates sometimes change driver settings or install new drivers that conflict with your graphics card. Restart your computer first—this often fixes temporary glitches. If glitches continue, open Device Manager, find your graphics card, right-click it, and select "Roll back driver" if that option appears. This reverts to the previous driver version. If rolling back doesn't work, update to the latest driver from the manufacturer's website.