Windows on MacBook Boot Camp Stops Connecting to External Displays

We recently repurposed an older MacBook to be the teenager’s main computer. I say “older” but it’s one of the later Intel-based models, and it’s still pretty fast for most everyday uses. He put a Windows partition on it with Boot Camp so he could dual-boot and play PC games that don’t run on macOS.

Somewhere along the line, Windows stopped connecting to external displays. MacOS had no problem with it, so it was clearly software and not hardware. (Always check the cables.)

Uninstalling and reinstalling the GPU driver didn’t work…in part because it couldn’t reinstall, throwing an error every time we tried.

What Fixed It

In Device Manager, we turned on Show Hidden Devices (in the View menu), which revealed another display adapter that was installed, but not active. Once we uninstalled that device (and rebooted just to be sure), the valid driver could actually install itself, and after another reboot, Windows was able to use an external monitor again!

What Broke It to Begin With?

VMWare on macOS can run a virtual machine from a Boot Camp partition, which sounds useful at first. But of course, it needs to install drivers for its virtual hardware. When you boot directly into Windows again, the drivers and device configuration are still there, but the virtual hardware isn’t.

The VMWare “display” was interfering with the driver for the real hardware, so Windows was falling back to a generic driver. That generic driver could run the built-in display on the laptop, but no more. But since the virtual hardware wasn’t present, Windows wasn’t saying anything about it. 🤦