What Is VirtualBox and How Does It Work?
Oracle VirtualBox is free, open-source virtualization software that lets you run a separate operating system inside your existing computer. For example, you can run Ubuntu Linux on a Windows 11 PC without replacing or modifying your current setup.
VirtualBox runs as a Type 2 hypervisor, meaning it sits on top of your existing OS and uses your computer’s hardware to power virtual machines. Each VM gets its own virtual CPU, RAM, storage, and network interface.
Before getting started, here are a few terms you’ll encounter throughout this guide:
- Host OS: The operating system installed on your physical computer (e.g., Windows 11).
- Guest OS: The operating system running inside a virtual machine (e.g., Ubuntu).
- VM (Virtual Machine): A software-based computer that runs a guest operating system independently.
- Virtual Hard Disk: A file that acts as the VM’s storage drive. VirtualBox supports VDI, VHD, and VMDK formats.
- ISO file: A disk image used to install an operating system in a virtual machine.
VirtualBox is commonly used to run Linux on a Windows PC, test software in an isolated environment, or explore a different OS without touching your main system.
How to Download and Install VirtualBox
Before creating a virtual machine, you need to install VirtualBox on your computer. The steps below use Windows 11 as an example. The process is similar on macOS and Linux, though some options differ.
Check the System Requirements
Make sure your computer meets the basic requirements before downloading:
- Operating system: A supported 64-bit version of Windows, macOS, or Linux.
- Processor: A 64-bit CPU with hardware virtualization support (Intel VT-x or AMD-V).
- RAM: At least 8 GB is a practical starting point, as you will need enough memory for both the host and guest OS to run at the same time.
- Storage: Enough free disk space for VirtualBox itself and any virtual machines you plan to create.
Note: Hardware virtualization is sometimes disabled by default. On Windows, you can check whether it is enabled by opening Task Manager, selecting the Performance tab, and clicking CPU. Look for the Virtualization row — it should say Enabled.
Download VirtualBox from the Official Website
Download VirtualBox directly from Oracle’s website to get the latest stable version.
- Go to the VirtualBox Downloads page at virtualbox.org.
- Under VirtualBox platform packages, click Windows hosts to download the Windows installer.
- Save the
.exe file to your computer and wait for the download to finish.
Note: If you are running Windows 11 on an ARM-based machine, a separate experimental installer is available on the same page.
Install and Launch VirtualBox
Once the download is complete, run the installer to set up VirtualBox:
- Double-click the downloaded
.exe file to launch the setup wizard.
- Click Next to proceed through the welcome screen.
- On the Custom Setup page, leave the default components selected unless you have a specific reason to change them, then click Next.
- A warning will appear noting that installing the VirtualBox network feature will temporarily reset your network connection. Click Yes to continue.
- Click Install to begin the installation.
- If a User Account Control (UAC) prompt appears, click Yes to allow the installer to make changes.
- Click Finish when the setup completes. VirtualBox will launch automatically if the checkbox is selected.
After installation, you can open Oracle VirtualBox from the Start menu at any time. The VirtualBox Manager window is where you will create and manage all your virtual machines.
How to Create a Virtual Machine in VirtualBox
After installing VirtualBox, you can set up a virtual machine to run a separate operating system. Each VM gets its own virtual hardware, including CPU, memory, and storage.
Choose a Name and Operating System
- Open VirtualBox Manager.
- Click New to open the virtual machine creation wizard.
- Enter a name for your VM.
- Select the folder where you want to store the VM files.
- Under ISO Image, select your installation ISO if you already have one downloaded. If not, leave it empty and continue.
- Set the Type and Version to match your chosen OS, such as Linux and Ubuntu (64-bit).
Allocate RAM and CPU Resources
Next, assign hardware resources to your VM.
- Set the Base Memory. For Ubuntu, 4 GB (4096 MB) is a reasonable starting point.
- Set the Processors value. Two CPU cores are sufficient for most basic tasks.
- Stay within the green range shown in VirtualBox to avoid affecting your host system’s performance.
Tip: Avoid over-allocating RAM or CPU to a VM. Your host OS needs those resources to keep running alongside it.
Create a Virtual Hard Disk
- Select Create a New Virtual Hard Disk.
- Set the file location and drag the slider to choose a disk size. 25 GB or more is a practical starting point for a basic Ubuntu installation.
- Select a disk format under Hard Disk File Type and Format. VDI (VirtualBox Disk Image) is the default and works well for most use cases.
- Check Pre-allocate Full Size if you want the full disk space reserved immediately, which can offer slightly better performance. Leave it unchecked to let the disk file grow as data is added.
- Click Finish to create the virtual hard disk.
Review and Save the VM Configuration
Before finishing, review your VM settings.
- Check the VM name, OS type, RAM, CPU count, and virtual disk size.
- If everything looks correct, click Finish to create the VM.
- Your new VM will appear in the left panel of VirtualBox Manager.
The VM is now ready, but it does not have an operating system installed yet.
How to Install an Operating System in VirtualBox
After creating a VM, the next step is installing a guest operating system. This requires an OS installation ISO file, which acts as a virtual installation disc.
Download the Operating System ISO File
Always download ISO files from the official source for the OS you want to install.
- Go to the official website of your chosen operating system.
- Find the download page and select the appropriate version for your needs.
- Download the ISO file and note where it is saved on your computer.
For example, you can get Ubuntu from ubuntu.com/download/desktop, or Windows 11 from Microsoft’s Windows 11 download page.
Tip: If you are unsure which Ubuntu version to install, see our guide to
Ubuntu versions for a quick overview.
Attach the ISO File and Install the Guest OS
If you did not select an ISO during VM creation, you can attach it manually before starting the VM.
- Open VirtualBox Manager and select your VM.
- Click Settings and open the Storage tab.
- Under the storage controller, select the empty optical drive.
- Click the optical disk icon on the right and choose Choose a Disk File.
- Browse to your downloaded ISO file and click Open.
- Click OK to save the changes.
After saving, you can reopen Settings > Storage to confirm the optical drive now shows your ISO file name instead of Empty.
Once the ISO is attached, click the arrow next to Start in VirtualBox Manager and select Start with GUI.
VirtualBox 7.x includes an unattended installation option for compatible OS images. If you prefer to follow the installation steps manually, select Skip Unattended Installation when creating the VM.
The VM will boot from the ISO and launch the OS installer. For Ubuntu, follow the on-screen steps to select a language, set up your keyboard layout, and create a user account. When the installation finishes, restart the VM when prompted.
How to Configure and Use VirtualBox
Once your guest OS is installed, you can adjust a few VirtualBox settings to improve usability and connect the VM with your host computer.
Install VirtualBox Guest Additions
Guest Additions is a package of drivers and utilities that improves integration between the host and guest OS. It enables features such as higher display resolution, shared clipboard, and drag-and-drop support.
- Start your VM and log in to the guest OS.
- In the VM window menu bar, click Devices.
- Select Insert Guest Additions CD Image.
- Open the mounted virtual CD inside the guest OS.
- Run the installer and follow the on-screen instructions.
- Restart the VM to apply the changes.
Note: On Windows guests, run VBoxWindowsAdditions.exe. On Linux guests, you may need to install build tools and kernel headers before running VBoxLinuxAdditions.run.
Configure Shared Folders and Clipboard
Shared folders let you transfer files between your host and guest OS without using external storage.
- Shut down the VM.
- Open VirtualBox Manager, select your VM, and click Settings.
- Go to Shared Folders and click the Add Shared Folder icon.
- Under Folder Path, select a folder on your host computer.
- Enter a name for the shared folder and check Auto-mount if you want it to appear automatically when the VM starts.
- Click OK to save the settings.
- Start the VM and access the shared folder from within the guest OS.
To enable clipboard sharing, go to Devices > Shared Clipboard in the VM window menu and select Bidirectional.
Tip: Shared clipboard and shared folder support require Guest Additions to be installed first.
For sharing files across different machines on the same network, see our guide to sharing files between computers.
Configure VirtualBox Network Settings
VirtualBox provides several network modes that control how your VM connects to other devices and the internet.
- Shut down the VM.
- Open Settings > Network.
- Under Adapter 1, make sure Enable Network Adapter is checked.
- Select a mode from the Attached to dropdown.
- Click OK to save.
The most common network modes are:
- NAT: The VM accesses the internet through the host’s connection. This is the default and works for most basic use cases.
- Bridged Adapter: The VM connects directly to the physical network and appears as a separate device.
- Host-only Adapter: The host and VM can communicate with each other, but the VM has no access to external networks.
- Internal Network: Allows communication between VMs on the same internal network, with no host or internet access.
For most beginners, NAT is sufficient to get started.
Adjust Display and Other VM Settings
You can change display and hardware settings to get better performance from your VM.
- Open VirtualBox Manager, select your VM, and click Settings.
- Open the Display tab.
- Increase Video Memory if the guest OS feels slow or the display looks low-quality.
- Enable 3D Acceleration if your hardware supports it and your guest OS requires it.
- Use the System or USB tabs to adjust other hardware options as needed.
- Click OK to save your changes.
Note: Features like automatic resolution adjustment work best after Guest Additions is installed.
How to Manage Virtual Machines in VirtualBox
VirtualBox includes several tools to control your VM’s operation, preserve its state, and create copies for testing or reuse.
Start, Pause, Save, and Shut Down a VM
You can control a running VM directly from the Machine menu in the VM window:
- Start: Select a VM in VirtualBox Manager and click Start to launch it.
- Pause: Select Machine > Pause to temporarily suspend the VM without closing it.
- Save State: Select Machine > Close > Save the Machine State to save the current session and resume it later from the same point.
- Shut Down: Use the guest OS’s normal shutdown option, or select Machine > ACPI Shutdown to send a shutdown signal to the guest.
- Power Off: Select Machine > Close > Power Off the Machine to stop the VM immediately. This is equivalent to cutting power to a physical computer and may result in data loss or file corruption.
Create and Restore VirtualBox Snapshots
Snapshots record a VM’s state at a specific point in time, so you can roll back if something goes wrong.
- Select a VM in VirtualBox Manager.
- Open the Snapshots view from the top-right menu.
- Click Take to create a new snapshot.
- Enter a name and description for the snapshot.
- Click OK to save it.
- To restore a snapshot, select it from the snapshot list and click Restore.
Tip: Take a snapshot before installing unfamiliar software or making major changes to the guest OS.
Snapshots are useful for quick rollbacks, but they are not a substitute for proper backups. For a closer look at the differences, see our guide on backup vs snapshot.
Clone and Export a Virtual Machine
VirtualBox lets you duplicate or export VMs for reuse, testing, or migration to another machine.
To clone a VM:
- Select the VM in VirtualBox Manager.
- Go to Machine > Clone.
- Enter a name for the new VM.
- Choose a clone type:
- Full Clone: Creates a fully independent copy with its own virtual disk files.
- Linked Clone: Shares virtual disk files with the original VM to save storage space, but depends on the original remaining available.
- Select which snapshot state to clone from, if applicable.
- Click Finish to create the clone.
To export a VM:
- Select the VM in VirtualBox Manager.
- Go to File > Export Appliance.
- Select the VM and click Next.
- Choose an export location and file name.
- Select the appliance format. OVA packages everything into a single file, while OVF exports as separate files.
- Review the settings and click Finish.
The exported file can be imported into another VirtualBox installation or any compatible virtualization platform.
FAQs About VirtualBox
Q1: Is VirtualBox free to use?
Yes. VirtualBox is free and open-source under the GNU General Public License (GPL). The Extension Pack, which adds USB 2.0/3.0 support and other features, has a separate license.
Q2: How much RAM should I give a VirtualBox VM?
For Ubuntu, 4 GB is a practical starting point. Windows guests typically need more. Leave at least half your total RAM available for the host OS.
Q3: Why is my VirtualBox VM running slowly?
Common causes include insufficient RAM or CPU allocation and disabled hardware virtualization. Check your VM resource settings and confirm that Intel VT-x or AMD-V is enabled in your BIOS or UEFI.
Q4: What is the difference between VirtualBox and VMware?
VirtualBox is free and open-source, while VMware offers commercial and free products with broader enterprise features. For a full comparison, see our VirtualBox vs VMware guide.
Q5: How do I share files between my computer and a VirtualBox VM?
Install Guest Additions, then add a shared folder under Settings > Shared Folders. Check Auto-mount to make it available automatically when the VM starts.
Conclusion
VirtualBox is a straightforward way to run a second operating system on your existing computer without any hardware changes. Once you have created a VM and installed a guest OS, you can use snapshots, shared folders, and network settings to build a setup that fits your needs.
For personal use and development testing, VirtualBox snapshots let you quickly roll back changes. However, snapshots are not backups — if the virtual disk itself is lost or corrupted, snapshots cannot help you recover it.
For businesses that run virtual machines in production environments, a dedicated backup solution is worth considering. i2Backup supports agentless VM backup across VMware, Hyper-V, and other major virtualization platforms, with fast recovery options to minimize downtime. Visit Info2soft to learn more about enterprise data protection.
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