Your monitor is likely going to sleep due to power settings, or cycling because of a loose cable or graphics card problem

A monitor that turns off and on repeatedly is almost always caused by one of three things: your computer's power management settings are putting the display to sleep, a cable connection is loose or damaged, or your graphics card is having trouble communicating with the monitor. The good news is that each of these has a straightforward fix, and you can test them in order without any special tools.

The most common culprit is power management — Windows and Mac both have settings that automatically turn off your display after a period of inactivity. If your monitor goes dark for a few seconds and then comes back on, that is usually what is happening. A loose cable or a graphics card driver problem causes a different pattern: the monitor may flicker, go black, or cycle on and off in rapid succession, sometimes with a "no signal" message appearing briefly.

Key Takeaways

  • Check your power settings first — Windows and Mac both have display timeout settings that turn off your monitor automatically after a set time of inactivity.
  • Inspect both ends of your monitor cable for loose connections, and try reseating the cable by unplugging it for ten seconds and plugging it back in firmly.
  • If you see a "no signal" message or rapid flickering, restart your computer and check for graphics driver updates through Device Manager or your graphics card manufacturer's website.
  • Try a different cable or a different port on your graphics card or monitor to rule out hardware failure.
  • If the problem started after a Windows or Mac update, rolling back your graphics driver may restore stability.

Check your power management settings first

Windows and Mac both have built-in settings that turn off your display after a certain time without activity. On Windows, this is called "screen timeout." On Mac, it is called "Turn display off after." If your monitor goes dark completely and then comes back on when you move your mouse or press a key, this is almost certainly the cause.

On Windows 10 or 11, go to Settings > System > Display > Screen timeout. You will see two options: "On battery" and "When plugged in." If you are using a desktop monitor, change "When plugged in" to "Never" — this prevents the monitor from turning off while you are working. If you want the monitor to sleep after a period of inactivity (to save power), set it to a longer time, like 30 minutes, rather than the default 10 minutes.

On Mac, go to System Settings > Displays > Auto-brightness, then look for a setting called "Turn display off after" or similar (the exact name varies by macOS version). Set this to "Never" or to a time longer than your typical work session. You may also need to check Energy Saver settings: go to System Settings > General > Energy Saver and make sure "Put display to sleep when inactive" is set to a longer time or turned off.

Inspect and reseat your monitor cable

A loose or partially disconnected cable is the second most common cause of monitors turning off and on. This usually shows up as flickering, a "no signal" message, or the monitor going black for a second or two before coming back. The cable can work itself loose over time, especially if your desk gets bumped or if the cable is bent sharply.

Unplug your monitor from power completely. Then look at both ends of the cable connecting your monitor to your computer — one end plugs into the monitor, and the other plugs into your graphics card (on the back of your tower) or into your laptop. The connectors should be tight and fully seated. If you see any bent pins on a VGA or DVI connector, or if the connector looks damaged, that cable may need to be replaced.

Unplug the cable from both ends, wait ten seconds, and plug it back in firmly. You should hear or feel a small click when the connector is fully seated. Plug your monitor back into power and turn it on. If the problem stops, the cable was loose. If it continues, try a different cable of the same type — borrow one from another monitor if you have one available, or purchase an inexpensive replacement to test.

Update or roll back your graphics driver

Your graphics card communicates with your monitor through a driver — software that tells your computer how to send images to the display. If this driver is outdated, corrupted, or recently updated and broken, your monitor may cycle on and off or show "no signal" messages. This is especially common right after a Windows or Mac update.

On Windows, right-click the Start button and select Device Manager. Look for "Display adapters" and click the arrow to expand it. You will see your graphics card listed — it might say NVIDIA, AMD, Intel, or another manufacturer. Right-click it and select "Update driver." Windows will search for a newer version. If one is found, install it and restart your computer.

If updating does not help, or if the problem started right after an update, you can roll back to the previous driver. In Device Manager, right-click your graphics card again, select "Properties," go to the "Driver" tab, and click "Roll Back Driver." This will restore the version you were using before the most recent update. Restart your computer and test.

On Mac, graphics drivers are usually updated through System Updates, so go to System Settings > General > Software Update and install any available updates. If the problem started after an update, you may need to contact the graphics card manufacturer (Apple, AMD, or NVIDIA) for a rollback option, as Mac does not have a built-in driver rollback feature.

Try a different port or cable type

Modern monitors and graphics cards often have multiple connection options — HDMI, DisplayPort, USB-C, or older standards like DVI or VGA. If your monitor has more than one input port, try plugging your cable into a different one. Sometimes a single port fails while others work fine.

If your graphics card has multiple video outputs, try a different one. For example, if you are using the HDMI port, try DisplayPort instead, or vice versa. This helps you determine whether the problem is with a specific port or with the cable itself. If the monitor works fine when plugged into a different port, that original port may be failing and will need to be replaced or repaired.

If you only have one type of cable available, borrow or purchase a different cable of the same type to test. A cable that looks fine on the outside can have internal damage that causes intermittent connection problems. Testing with a known-good cable is the fastest way to rule out cable failure.

Restart your computer and check for hardware conflicts

Sometimes a straightforward restart clears up temporary communication problems between your graphics card and monitor. Shut down your computer completely (not sleep mode), wait 30 seconds, and turn it back on. This resets the connection between all hardware components.

If the problem persists and you see rapid flickering or "no signal" messages, the issue is likely hardware-related rather than a software setting. At this point, you have already tested the cable and tried driver updates. The remaining possibilities are a failing graphics card, a failing monitor, or a port that is not making good contact.

If you have access to another monitor, plug it into your computer using the same cable and port. If the second monitor works fine, your original monitor may be failing. If the second monitor has the same problem, your graphics card or its driver is the issue. This straightforward swap tells you which piece of hardware to focus on.

When to replace your monitor or graphics card

If you have worked through all the steps above and the problem continues, you are likely dealing with a hardware failure. A monitor that cycles on and off despite having a good cable, updated drivers, and a working graphics card is probably failing internally. Similarly, a graphics card that cannot maintain a stable signal to any monitor, even with different cables and ports, is likely defective.

Before you replace anything, try one more test: connect your monitor to a different computer if you have access to one. If the monitor works perfectly on another computer, your graphics card or its driver is the problem. If the monitor fails on the second computer too, the monitor itself is failing and needs to be replaced. Most monitors have a one- to three-year warranty, so check your receipt or the manufacturer's website to see if yours is still covered.

Frequently Asked Questions

Why does my monitor say "no signal" and then turn back on?

This usually means your graphics card is losing communication with the monitor, most often due to a loose cable, a failing port, or an outdated driver. Start by reseating your cable — unplug both ends, wait ten seconds, and plug back in firmly. If that does not work, update your graphics driver through Device Manager (Windows) or System Settings (Mac).

My monitor turns off after 10 minutes of not using it. How do I stop that?

Your power settings are set to turn off the display after inactivity. On Windows, go to Settings > System > Display > Screen timeout and change "When plugged in" to "Never." On Mac, go to System Settings > Displays and set "Turn display off after" to "Never."

The monitor flickers constantly. Is it the cable or the monitor itself?

Constant flickering is usually a cable problem. Try reseating your current cable, then test with a different cable if you have one available. If flickering stops with a different cable, your original cable is bad. If it continues with a new cable, try a different port on your graphics card or monitor. If flickering persists across multiple cables and ports, the monitor or graphics card is likely failing.

My monitor started turning off and on after a Windows update. What should I do?

A recent update may have broken your graphics driver. Open Device Manager, find your graphics card under "Display adapters," right-click it, and select "Roll Back Driver" to restore the previous version. Restart your computer and test. If rollback is not available, update to the latest driver from your graphics card manufacturer's website.

Can a loose power cable cause my monitor to turn off and on?

Yes, but less commonly than a loose video cable. Check that the power cable is fully plugged into both the monitor and the wall outlet. However, if the monitor is turning off and on while staying powered on (rather than losing power completely), the issue is almost always the video cable or driver, not the power connection.