Read on for our selection of fixes for when your second monitor goes missing. Do note that this article only deals with the Windows platform.
Are You in the Correct Port?
Starting with the simple stuff, we’ll skip the Route-1 advice to check for loose connections (and try different cables) and go for the slightly more advanced issue of your second monitor not being connected to the right port. If you have a dedicated graphics card, then all visual output connections go from there, so any monitor cables (VGA, HDMI, DVI, whatever) you connect to the motherboard boards won’t work. If you want to use both your motherboard and GPU ports (because, for example, your graphics card doesn’t have a VGA port and you want to hook up a VGA monitor alongside your HDMI one), you can potentially do so by going to your PC BIOS, and setting your integrated/motherboard as your primary display adapter. Your drivers should still pick up your graphics card this way, yet your motherboard ports will be active at the same time.
Force Windows to Detect Display
Most displays should be automatically detected by Windows as soon as you connect them (the shortcut for Multiple Display options is Win + P, letting you toggle different multiple-display setups if indeed there are multiple displays connected). However, this doesn’t always happen, whether because you’re using an older display or because of a software hiccup (use CCleaner to get rid of old registry keys, which could be causing conflicts in your display drivers). To get Windows to manually detect a second monitor, right-click on the desktop, click “Display settings”, then the “Detect” button under “Multiple displays”.
Reinstall or Roll Back Graphics Card Driver
If you started experiencing this problem since a GPU driver update, then it’s quite possible that that’s where your problem stems from. To solve this, you can try rolling back the driver to the previous version. The best way to do this is to go to Device Manager, find your graphics card under “Display adapters”, right-click it, then click “Properties”. Then click the “Driver” tab, select “Roll Back Driver”, and follow the instructions to do so. Reboot your PC, and hopefully your second screen will work again. You could even try updating back to the latest driver version after you reboot, or to be safe you can wait until an even more recent version of the driver gets released. While you’re in the Device Manager, you could also try the above process for your second monitor. Find it under the “Monitors” dropdown in Device Manager, and do the same thing.
Conclusion
The above selection of fixes for a blank second monitor should get it beaming again. As ever, make the relevant checks to cables and by testing the second monitor as a main monitor so that you know for sure that it’s not a hardware issue.