Here’s the steps:

1. at the host (not the guest), open a ‘cmd’ window as administrator.
2. go to VBox Addtion directory (e.g. C:\Program Files\Oracle\VirtualBox)
3. run the command.
4. start your VM.
5. at the VM, use HOME+F to switch to the full screen mode which is 4k at my display monitor.

How do I fix my VM resolution?

Procedure

1. Select Window > Virtual Machine Library.
2. Select a virtual machine in the Virtual Machine Library window and click Settings.
3. Under System Settings in the Settings window, click Display.
4. Select the Single Window resolution setting.
5. Select the Full Screen resolution setting.

How do I make my monitor 16 9?

The process of setting the resolution on your widescreen computer monitor is fairly simple and straightforward.

1. Launch Control Panel. To get to the settings, you will have to go through the Control Panel.
2. Adjust Screen Resolution.
3. Check For Changes.
4. Choose Resolution.
5. Select Orientation.
6. Save Settings.

How to enable auto-resizing screen resolution in VirtualBox guest Linux system?

Auto-resize screen in Virtualbox guest Linux system. To enable auto-resizing screen resolution for Linux guest you should use the VBoxVGA virtual graphics controller(Machine Settings – Display – Graphics Controller). This is a tricky part, because “Create Virtual Machine” dialog by default chooses the VMSVGA controler for new Linux machines.

Why can’t I get the full screen on my VirtualBox?

On virtualbox with debian, the full screen doesn’t work by default. Fortunately it’s possible to correct this fairly quickly. Like 99.99% of people, you miss a thing called Guest Additions. They are not avaible and so you have this full screen issue when you use Virtual Box with windows.

How to find supported resolution in Grub shell?

In my case DesiredResolution=1280×1024. The resolution here must be a supported resolution. You can find a list of supported resolution by booting up to grub, running the grub shell then executing the vbeinfo command. Restart your machine. Thanks for contributing an answer to Unix & Linux Stack Exchange!