What causes screen glitches and how to start fixing them
A screen glitch is usually one of three things: a loose cable, outdated or corrupted graphics drivers, or a display setting that has changed. Most of the time you can fix it yourself in under an hour by checking the physical connection first, then restarting your computer, then updating your graphics driver. If the glitch only happens in one program, the problem is almost always that program, not your monitor or graphics card.
The fastest way forward is to identify what the glitch looks like. Flickering, lines, color shifts, and frozen sections each point to different causes. A glitch that appears only when you move your mouse or open a specific program behaves differently than one that happens constantly, and that difference tells you where to look first.
Key Takeaways
- Check that your monitor cable is fully plugged into both the back of your computer and the monitor itself, as loose connections cause most screen glitches.
- Restart your computer completely — power off, wait 30 seconds, then power back on — before trying anything else.
- Update your graphics driver through Device Manager (Windows) or System Preferences (Mac), as outdated drivers cause flickering and color problems.
- If the glitch only happens in one program, uninstall and reinstall that program rather than troubleshooting your entire display.
- Adjust your refresh rate in display settings if you see constant flickering, as a mismatch between your monitor and computer settings causes this.
Check your monitor cable and power connection
Before you change any settings, make sure the cable connecting your monitor to your computer is fully seated on both ends. Power off your computer and monitor, then unplug the monitor cable from the back of the computer tower or laptop dock. Wait five seconds, then plug it back in firmly until you hear or feel a click. Do the same at the monitor end.
If you are using an older monitor with a VGA cable (the one with blue ends and small screws), tighten those screws by hand after plugging it in. Loose VGA connections are a common cause of flickering and color shifts. Check that your monitor's power cable is also plugged in and that the outlet works — plug a lamp into the same outlet to confirm.
Power your computer back on and watch the screen for 30 seconds. If the glitch is gone, you are done. If it remains, move to the next step.
Restart your computer completely
A full restart clears temporary files and resets your graphics settings without changing anything permanent. Do not use sleep mode or restart — power off completely. On Windows, click the Start menu, select Power, and choose Shut Down. On Mac, click the Apple menu and select Shut Down. Wait 30 seconds with the computer off.
Power the computer back on and let it fully load. Watch for the glitch during startup and while you use the computer normally for a few minutes. Many glitches disappear after a restart because they are caused by temporary memory conflicts or driver hiccups that clear when the system resets.
Update your graphics driver on Windows
Your graphics driver is the software that tells your computer how to talk to your monitor. Outdated drivers cause flickering, color problems, and display lag. On Windows, right-click the Start menu and select Device Manager. Look for Display adapters and click the arrow next to it to expand the list.
Right-click the graphics card listed there (usually Intel, NVIDIA, or AMD) and select Update driver. Choose Search automatically for updated driver software. Windows will search for the latest version online and install it if one is found. You may need to restart your computer after the update finishes.
If Windows says your driver is already up to date but you still see glitches, visit the manufacturer's website directly. Go to Intel.com, NVIDIA.com, or AMD.com, find the drivers section, and read the latest driver for your specific graphics card model. Run the installer and follow the prompts, then restart your computer.
Update your graphics driver on Mac
Mac updates graphics drivers automatically through System Updates, so you do not need to visit a separate website. Click the Apple menu, select System Settings, then click General on the left. Select Software Update and let your Mac check for updates. If any are available, click Update Now and restart when prompted.
If you have an older Mac with an Intel processor and an NVIDIA graphics card, visit NVIDIA.com directly, as Apple no longer provides NVIDIA drivers through System Updates. read the latest driver for your Mac model, run the installer, and restart.
Adjust your refresh rate if you see flickering
Refresh rate is how many times per second your monitor redraws the image on screen. If your computer is set to a refresh rate your monitor does not support, you will see constant flickering. On Windows, right-click your desktop and select Display settings. Scroll down and click Advanced display settings. Look for Refresh rate and click the dropdown. Try the highest number available, then click explore.
On Mac, click the Apple menu, select System Settings, then click Displays. Click the dropdown next to Refresh rate and select the highest option available. The change takes effect when ready. If the flickering stops, you have found the problem. If it continues, change the refresh rate back to what it was and try the next step.
Uninstall and reinstall a program if the glitch only happens there
If the screen glitch only appears when you use one specific program — like a web browser, game, or photo editor — the problem is that program, not your monitor or graphics driver. Uninstall the program, restart your computer, then read and install the latest version from the official website.
On Windows, go to Settings, select Apps, find the program in the list, click it, and select Uninstall. On Mac, open Applications in Finder, drag the program to Trash, then empty Trash. After you restart, visit the program's official website and read the newest version. Install it and test whether the glitch is gone.
When to replace your monitor or graphics card
If you have checked the cable, restarted, updated drivers, and adjusted refresh rate, but the glitch persists across all programs, your monitor or graphics card may be failing. A monitor that flickers even after a driver update and refresh rate adjustment, or one that shows the same glitch on a different computer, is likely defective and needs replacement.
A graphics card that causes glitches in every program but works fine when you use integrated graphics (built into your processor) is also likely failing. If you have a dedicated graphics card, you can test this by disabling it in Device Manager and using your computer's built-in display output instead. If the glitch disappears, the dedicated card is the problem.
Frequently Asked Questions
Why does my screen flicker only when I move my mouse?
This usually means your monitor cable is loose or your refresh rate is too low for your monitor. Check the cable connection first, then try raising your refresh rate in display settings. If flickering stops when you move the mouse slowly, your graphics driver may also need an update.
Can a software update cause screen glitches?
Yes. A Windows or Mac system update can sometimes reset your graphics driver or display settings. If glitches started right after an update, restart your computer first, then check for graphics driver updates. You may also need to adjust your refresh rate again if the update changed it.
What if my screen glitch only happens when I use a specific website or app?
The problem is that website or app, not your computer. Try clearing your browser cache if it is a website, or uninstall and reinstall the app. If the glitch continues in that one place only, contact the website or app developer — your graphics driver and monitor are working correctly.
Does a screen glitch mean my computer is overheating?
Overheating usually causes your computer to slow down or shut off, not screen glitches. Screen glitches point to driver, cable, or display setting problems. That said, if your computer is very hot to the touch and you see glitches, shut it down, let it cool for 30 minutes, and check that your fans are not blocked by dust.