The second monitor is not detected
I connected a second screen and nothing appears on it.
Written by The CommonFixes team · fact checked by CommonFixes review desk
Last updated
Short answer
The cable, the input choice on the monitor, and the projection mode all have to line up before a picture appears. The quickest thing to try first: set the projection mode — Press Windows and P and choose Extend. On a Mac, open System Settings, Displays, and click Detect Displays. Most people are done in about 10 minutes.
Full walkthrough below: 5 steps for Windows and Mac, rated easy.
Sounds like this
- •Monitor says no signal
- •Only one screen in display settings
- •Works when unplugged and replugged
Why it happens
The cable, the input choice on the monitor, and the projection mode all have to line up before a picture appears.
Work through these in order
0% done- 1
Set the projection mode
Press Windows and P and choose Extend. On a Mac, open System Settings, Displays, and click Detect Displays.
- 2
Choose the right input on the monitor
Use the monitor buttons to select the input you actually plugged into, such as HDMI 1 or DisplayPort. Monitors do not always switch on their own.
- 3
Swap the cable
Faulty and low quality HDMI cables are a very frequent cause. Borrow a known good one to test.
- 4
Force detection
Open Settings, System, Display, expand Multiple displays, and click Detect.
- 5
Update the graphics driver
Download the latest driver directly from Intel, AMD or NVIDIA. Multi-screen support improves with almost every release.
If none of that worked
Check whether the port belongs to the graphics card or the motherboard on a desktop. Plugging into the wrong one is a classic mistake.
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Who wrote this and how we checked it
The CommonFixes team
Writer and researcher
We are a small group of people who spend our days repairing laptops and desktops for family, friends and small offices. Every guide here starts with a problem someone actually brought to us, and we only write down the steps that put the machine right.
- Everyday repairs
- Windows and Mac
- Plain language
CommonFixes review desk
Technical editor
Before a guide goes live, a second person walks through it on a real machine and checks each instruction against the maker's own support pages. Anything we cannot confirm is removed rather than guessed at.
- Fact checking
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This guide was last updated on 10 August 2026. If a step no longer matches what you see on screen, tell us on the contact page and we will test it again.
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