Troubleshooting when External Monitors stop working

Summary

This article has some steps to try if your external monitors are not working.

Environment

Equipment:

• Windows computer connected to external display monitors, either directly or through a docking station.
• Apple Mac computer connected to external display monitors using a dongle or special cord.

Issue

Your computer or laptop is connected to one or more external display monitors, but there is no image on either one or both of the monitors.

Resolution

General troubleshooting steps - try these first

1. If your laptop is plugged in through a "dock", first try resetting the dock to see if that solves the problem.  Instructions in article - Laptop: Resetting a USB-C/Thunderbolt Dock
2. Verify that each external monitor is plugged in and getting power – there should be lights somewhere on the monitor, possibly briefly.  Pushing the power button on and off should show you something on the monitor screen.
3. Check that the external display monitor connections are all secure – push the ends of each connecting cord in securely, to be sure it is connected well.
4. Be sure your computer has all its latest Updates.  Check for operating system updates and install any outstanding updates if they exist.

If these steps do not solve the problem, then try the steps below for your Windows or Apple Mac computer.

Windows troubleshooting steps

Note: If your laptop is plugged in through a "dock", first try resetting the dock to see if that solves the problem.  Instructions in article - Laptop: Resetting a USB-C/Thunderbolt Dock

Step 1 – Press the Windows logo key + P to view the Windows “Project” menu.

Step 2 – Be sure that the “Extend” option is selected.  If it is not, click on “Extend”.

Result

This will often solve the issue of an external display monitor not working.

If you are still having issues, you can try additional steps in this Microsoft support article - Troubleshoot external monitor connections in Windows 10 

Apple Mac troubleshooting steps

Note: If your laptop is plugged in through a "dock", first try resetting the dock to see if that solves the problem.  Instructions in article - Laptop: Resetting a USB-C/Thunderbolt Dock

Step 1 – Unplug and re-plug each end of the dongle or cord connecting your Apple Mac computer to the external monitor.

Step 2 – Repeat for each end of every cord or dongle and for each external monitor.

Result

This will often solve the issue of an external display monitor not working.

Further Readings

Laptop: Resetting a USB-C/Thunderbolt Dock

Troubleshoot external monitor connections in Windows 10 

Need additional help?

Visit the Technology Help Desk Support page to locate your local campus contact information or to submit an online technology support request.  For password issues you must call or visit the Help Desk in person.