Oracle’s VirtualBox virtualization software is a popular choice for users who want to test new versions of the operating system. If you install Windows in VirtualBox, you may notice that you cannot change the default screen resolution of 1024×768.
The low resolution may be sufficient for some tasks, but many can benefit from higher resolutions. The View > Virtual Screen menu in the VirtualBox application lists all available resolutions and scaling options.
The “resize to” options are all inactive, as they are grayed out and not selectable. Scaling options are unlocked and available, however.
Luckily, it’s pretty easy to unlock all supported screen resolutions in VirtualBox. The following instructions explain in detail how to do this.
Fix Windows screen size in VirtualBox
The fix requires the installation of Guest Additions; It may seem daunting at first, but it’s a simple process that completes in minutes on most systems. The description may give the impression that you would need to insert a CD image, but it is not. VirtualBox mounts a virtual CD image when the option is selected.
To get started, select Devices > Insert Guest Additions CD Image. All it does is mount the Guest Additions CD in VirtualBox, so you can access its contents. You will hear a sound indicating that the CD has been mounted.
Next, open File Explorer on the system and open the “Virtual Guest Additions” CD drive.
The root menu lists three guest additions for Windows. There are also additions for other operating systems, including Linux and Solaris.
The three Windows guest additions are for different architectures.
- VBoxWindowsAdditions is an autoselector. Choose this one.
- VboxWindowsAdditions-amd64 is a 64-bit system.
- VboxWindowsAdditions-x86 is for 32-bit systems.
Right-click on one of the files and select Open from the context menu to start the installation in the virtual machine. You can double click on the file to start the installation.
Windows displays a User Account Control prompt, which you must authorize by selecting Yes.
The installer launches after you select Yes. Select Next on the first page that appears.
The following page displays the destination folder for the files that will be installed. You can change it, but most users might want to keep the default path. Select Next to continue.
The final screen displays the components that will be installed. You can disable the creation of a Start menu entry, but the remaining two components will be installed. Select the install button to continue.
The installer displays its actions once you press the install button.
It is necessary to restart the virtual machine to complete the installation. You can do this immediately by selecting “restart now”, or later. Select Finish to exit the installer.
All screen resolutions are unlocked after reboot. Select Display > Virtual Screen X to select a different resolution. Please note that it may take a few seconds before the resolutions are available.
The physical display limits the available resolution; you cannot exceed the maximum resolution supported by the display.