Getting started with VirtualBox on Linux: From hobbyist tinkering to production prep

See how you can test new environments safely without risking your production setup.

I started using VirtualBox many years ago, and it quickly became my go-to virtualization platform. What drew me in first was its open source foundation. The base package, source code and binaries included, is licensed under GPLv3, making it a transparent and accessible option for anyone exploring virtual machines.

VirtualBox is also remarkably versatile. It runs on Linux, macOS (Intel and ARM), Windows, and even Solaris. Since its initial release in 2007, it has enjoyed continuous development, with steady improvements and frequent updates. The latest stable version, 7.2.4, shipped in October, a clear sign that the project remains active and evolving.

For me, though, VirtualBox is more than a piece of software. It’s a sandbox for learning and experimentation. I use it to test new Linux distributions, try out fresh Windows releases, and occasionally help others troubleshoot or validate configurations before deploying them in the real world.

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My daily driver setup

To put my workflow in context, my main workstation is a System76 Meerkat running Linux Mint 22.2. With 32 GB of RAM and a one-terabyte NVMe drive, it’s a compact but powerful machine. Virtualization is effortless on this setup; I can run multiple virtual machines with no noticeable slowdown thanks to the generous memory and fast storage.

Installing VirtualBox on Linux Mint is straightforward:

$ sudo apt install virtualbox

And for Fedora users:

$ sudo dnf install virtualbox

Within minutes, you can have a fully functional virtualization environment ready for whatever OS you want to explore.

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The dreaded VT-x error

Of course, not every moment is smooth sailing. When I first ran VirtualBox on my Linux Mint system, I hit a frustrating error:

VT-x is being used by another hypervisor (VERR_VMX_IN_VMX_ROOT_MODE).
VirtualBox can't operate in VMX root mode. Please disable the KVM kernel extension,
recompile your kernel and reboot (VERR_VMX_IN_VMX_ROOT_MODE).

It looks alarming, but the explanation is simple: Another hypervisor, in this case, KVM, is already using the VT-x virtualization extensions. Because both KVM and VirtualBox require VT-x, they can’t run simultaneously.

The fix: disabling KVM

Fortunately, the solution is quick. After a bit of searching, I found that unloading the KVM Intel kernel module frees up the virtualization extensions:

$ sudo modprobe -r kvm_intel

Once I ran that command, VirtualBox started without any issues. No kernel recompilation, no reboot required. This trick is now part of my routine whenever the VT-x error appears.

A real-world use case: Helping my dentist

One example shows just how practical VirtualBox can be. My dentist needed help setting up a Windows Server 2025 file server for his practice management system. Rather than risking changes on his production hardware, I spun up a test environment in VirtualBox. This allowed me to configure and validate everything safely before deploying it for real.

That flexibility is one of VirtualBox’s greatest strengths. You can simulate complex environments without extra equipment, expense, or risk, which is useful whether you’re a hobbyist tinkering with operating systems or a professional preparing for a production rollout.

Building a Windows Server test environment

I downloaded the Windows Server 2025 evaluation ISO from Microsoft (about 5 GB) and mounted it in VirtualBox as the installation media.

From there, I used VirtualBox’s built-in tools to configure storage and networking. The default 50 GB virtual disk worked fine for testing, though you can expand the size or attach additional drives if you want to explore more advanced layouts. I selected a bridged network adapter so the VM could communicate on my home network just like any other system. VirtualBox doesn’t support hardware RAID, but software RAID is perfectly workable for experimentation.

With the preliminary configuration done, I launched the VM and began the Windows Server installation. The process mirrors installing on physical hardware, though it runs noticeably faster in a virtual environment.

When everything finished, I had a clean Windows Server 2025 instance ready to explore. Testing each configuration in VirtualBox made the eventual real-world deployment far smoother and eliminated the risk of breaking my dentist’s production setup.

Final thoughts

My journey with VirtualBox has been one of exploration, learning, and practical utility. Whether I’m testing a new Linux distro or helping my dentist prep a Windows Server, VirtualBox consistently delivers a reliable and flexible environment.

If you’ve never tried VirtualBox, it’s absolutely worth exploring. Whether you’re on Linux, macOS, Windows, or Solaris, it offers a safe, powerful way to experiment and build your skills in the digital world.

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This article is adapted from “VirtualBox: A longtime companion in my tech journey” by Don Watkins, and is republished with permission from the author.