How to open a macOS VirtualBox virtual machine in full screen mode

Installed macOS using VirtualBox on your Windows PC only to find out it doesn’t work in full screen mode? Well, this is something that many new VirtualBox users experience, but it’s not really a problem. This can be solved with a simple command line.

When you use VirtualBox to run macOS in a guest environment, the operating system’s default resolution is set to 1024×768. Given that most people these days have at least Full HD 1080p monitors, it might seem like macOS is running in a small window. Even if you try to maximize the window, the guest OS won’t expand to fill the entire screen. To fix this, you need to match your virtual machine’s resolution to your monitor’s resolution.

Don’t know where to start? Don’t worry as we will help you with that here.

How to open a macOS VirtualBox virtual machine in full screen mode

Please note that these steps only work for VirtualBox and not for any other software like VMware Workstation.

1. First, download this file which contains the command line to change the screen resolution. This will make it easier for you to follow. Open a command prompt on your computer as an administrator and copy/paste the first line in the file. Press the enter key.

   

2. Next, you need to copy and paste the second line into the file. But before that, change the resolution to the resolution of your monitor. For example, if you have a 4K monitor, change the resolution to 3840×2160. After you have pasted the code, press the Enter key.

   

3. Then launch VirtualBox, select the macOS virtual machine in the left pane, and click Start to load it.

   

4. macOS will now load and fill your screen, but you will still see the VirtualBox window and menu items. To hide it and enter exclusive full screen mode, press the Ctrl + F keys on your keyboard.

   

Here you go. You have successfully configured your macOS virtual machine to run in full screen mode.

There is one thing you need to keep in mind when you upscale your VM, especially for higher resolutions like QHD and 4K. As you climb higher, macOS performance may degrade in VirtualBox as more resources are used. Therefore, it is better to leave the resolution at Full HD or lower in order to maintain a balance between performance and quality.

This is just one of the things that new VirtualBox users run into when setting up a guest environment. The other is connecting external USB devices. When you plug a device into a USB port, it is recognized by Windows and not by the guest OS. In order for macOS to detect your USB device, you need to connect it to a virtual machine using VirtualBox. You can learn more about connecting USB devices to VirtualBox right here.

I hope you were able to verify that your macOS virtual machine fills the entire screen on every boot. What screen resolution did you use on the command line? Did you notice the performance impact after upscaling the resolution? Share your experience with us and don’t be silent in the comments section below.