If your Mac isn’t detecting an external display or you’re facing connection issues, it’s often due to configuration settings, the cable used, or compatibility rather than a hardware fault with the Mac or monitor.
This guide outlines the most common causes of display issues and provides step-by-step solutions that are well worth trying to resolve the problem.
Check Physical Connections
- Check that the connection between your Mac and external display is secure at both ends.
- Inspect the cable for any signs of wear or damage.
- Test using an alternative cable, preferably an Apple-branded or Apple-certified option.
Confirm Display Input Source
- Check the input source settings on the display using the built-in menu (e.g. HDMI 1, DisplayPort, USB-C).
- Make sure the input setting on your display matches the port to which your Mac is connected to.
- If you're uncertain how to navigate these settings, consult the display's user guide or reach out to the manufacturer for support.
Try a Different Port
- If you’ve tried HDMI, consider using a Thunderbolt, USB-C to HDMI or DisplayPort adapter instead.
- Apple offers a range of certified adapters which are generally the most reliable for compatibility with Mac systems.
- When using a USB-C connection, ensure the cable is capable of video output as not all cables support display functionality.
- If you’re unsure, it’s always a good idea to contact Apple directly, they can recommend the most suitable cable and port configuration for connecting your specific Mac.
Detect Displays in macOS
- Go to System Settings > Displays.
- Hold the Option key and click Detect Displays.
Restart both Devices
- Switch your Mac and display off and switch them both back on.
Test with another Display
- Try connecting your Mac to another display or TV, this will help you check to see if it's a display-related issue.
Boot into Safe Mode
For Apple-silicon based devices:
- Power off your Mac completely.
- Press and hold the Power button until the “Loading startup options” screen appears.
- Select your startup disk (typically Macintosh HD).
- While holding the Shift key, click Continue in Safe Mode.
- Release the Shift key.
- Your Mac will now boot into Safe Mode, you’ll see “Safe Boot” in the top-right corner of the screen or under System Information.
Once in Safe Mode, check whether the external display is detected. If it is, this suggests the issue is likely software-related. In that case, updating macOS or performing a factory reset may help resolve the problem.
For intel-based devices:
- Power off your Mac completely.
- Switch on your device while holding the Shift key to initiate Safe Mode.
Once the system has booted, check whether the external display is recognised. If it is, this typically indicates a software-related issue. In such cases, updating macOS or performing a reinstall of macOS may help resolve the problem.
Update macOS
- Before you start make sure you backup your data.
- Navigate to System Settings > General > Software Update.
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Follow the on-screen prompts to update your device.
Reinstall macOS
⚠️ Important: Please note that these procedures will result in the complete removal of all data from your Mac.
- Backup the data on your device and check which Mac model you have, clicking here.
- Follow this guide if you're running macOS Monterey or later, with Apple Silicon or a T2 Security Chip.
- Follow this guide if you've tried step 2 already and/or if you have an Intel-based Mac.
- Test to see if the display works.
