Enable Fullscreen Mode

VirtualBox allows users to run virtual machines efficiently, but one common issue is the inability to achieve fullscreen resolution in the guest OS. The solution is to install or update VirtualBox Guest Additions. Follow these steps to enable fullscreen mode for your virtual machine.

Step 1: Update VirtualBox Guest Additions

If you are experiencing issues with fullscreen mode, the first step is to update Guest Additions. Sometimes, simply reinstalling VirtualBox can resolve compatibility problems.

Reinstall VirtualBox

1. Uninstall the existing VirtualBox installation.

2. Download the latest version from the official VirtualBox website.

3. Reinstall VirtualBox, ensuring that the Guest Additions ISO is included.

Step 2: Update the Virtual Machine

Before proceeding with the installation of Guest Additions, update your virtual machine to ensure all dependencies are current.

Run the following commands in the terminal:

apt update
apt upgrade -y

Step 3: Install Required Kernel Modules

Guest Additions require specific kernel modules to be installed for proper functionality. Install them using the following commands:

apt install build-essential module-assistant
m-a prepare

Step 4: Install VirtualBox Guest Additions on the Guest OS

Now, install Guest Additions to enable fullscreen mode and other enhancements like shared folders and improved graphics.

Mount the Guest Additions ISO

Run the following commands:

cd /media
mkdir cdrom # Optional: Sometimes unnecessary
mount /dev/cdrom /media/cdrom # Optional: Sometimes unnecessary

Run the Installer

cd /media/cdrom
sh VBoxLinuxAdditions.run

Once the installation is complete, reboot the virtual machine:

reboot

Step 5: Verify Fullscreen Mode

After rebooting, the guest OS should now automatically adjust to the full resolution of your display.

Additional Troubleshooting

• If fullscreen mode is still not working, reinstall Guest Additions.

• Ensure that "Auto-resize Guest Display" is enabled under the "View" menu in VirtualBox.

• Check that the VirtualBox graphics controller is set to VBoxSVGA under Settings > Display.