How to Create a VM (Virtual Machine): What You Need to Know Before You Start

Creating a virtual machine sounds technical, but the core idea is straightforward: you're running a second computer inside your existing computer. That second computer — the VM — behaves like real hardware, complete with its own operating system, storage, and memory. It just happens to exist entirely in software.

Whether you're testing a new OS, running legacy apps, or building a dev environment, the setup process follows a similar path — but the details vary quite a bit depending on your hardware, host OS, and what you're actually trying to accomplish.

What a Virtual Machine Actually Does

A VM works by using a piece of software called a hypervisor to divide your physical machine's resources — CPU, RAM, disk space — and allocate a share of them to a simulated environment. That environment runs its own OS independently of your host system.

There are two types of hypervisors:

• Type 1 (bare-metal): Runs directly on hardware, no host OS in between. Used in enterprise environments (VMware ESXi, Microsoft Hyper-V in server mode).
• Type 2 (hosted): Runs as an application on top of your existing OS. This is what most desktop users work with — VirtualBox, VMware Workstation, Parallels.

For most people creating their first VM, a Type 2 hypervisor is the starting point.

The Basic Process of Creating a VM 🖥️

Regardless of platform, the general steps follow the same pattern:

1. Choose Your Hypervisor Software

Popular options for desktop use include:

Your choice here isn't arbitrary — it depends heavily on your host OS, your guest OS target, and whether you're on Intel/AMD or Apple Silicon hardware.

2. Obtain a Guest OS Image

You'll need an ISO file — a disk image of the OS you want to install inside the VM. For Windows, that means downloading from Microsoft. For Linux distributions like Ubuntu, Debian, or Fedora, ISOs are available directly from each project's official website.

Keep licensing in mind: running Windows in a VM still requires a valid license.

3. Create a New VM and Configure It

Inside your hypervisor, you'll create a new virtual machine and define its specs:

• RAM allocation: How much of your host system's memory the VM can use
• CPU cores: How many logical processors to assign
• Virtual disk: A file on your host drive that acts as the VM's hard drive — you set the maximum size
• Network adapter: Usually set to NAT (shares your host's connection) or Bridged (VM gets its own network identity)

Most hypervisors offer a guided wizard that sets reasonable defaults based on the OS you select.

4. Install the Guest OS

Once the VM is configured, you attach the ISO as a virtual optical drive and boot the VM. From there, it's a normal OS installation — the VM doesn't know it's not running on real hardware.

After installation, it's worth installing Guest Additions (VirtualBox) or VMware Tools — these are packages that improve display resolution, clipboard sharing, and drag-and-drop between host and guest.

The Variables That Change Everything

Here's where individual setups diverge significantly:

Host hardware matters a lot. A VM competes with your host OS for CPU and RAM. On a machine with 8GB of RAM, allocating 4GB to a Windows VM leaves your host system thin. On 32GB, you have far more flexibility. Performance inside the VM is directly tied to what you're willing (and able) to give it.

Architecture is a real constraint. If you're on an Apple Silicon Mac (M1/M2/M3), you cannot run x86 Windows VMs the way you could on Intel. You'd need ARM versions of operating systems, or tools like UTM that handle emulation — which carries a performance cost.

Use case shapes configuration. A VM for light web browsing needs very different specs than a VM running a local development server, a database, or graphical software. Oversizing wastes host resources; undersizing makes the VM sluggish and frustrating.

Nested virtualization — running a VM inside a VM — is possible on some setups but requires CPU support (Intel VT-x/AMD-V enabled in BIOS) and adds complexity that not every platform handles cleanly.

Snapshots, Storage, and Practical Considerations 💾

One of the most useful VM features is snapshots — saved states of the VM at a point in time. You can break something, roll back instantly, and try again. This makes VMs ideal for testing software, experimenting with system configurations, or learning without risk.

Virtual disk storage can be either dynamically allocated (grows as needed, up to a max size) or fixed size (pre-allocates all space immediately). Fixed-size disks generally perform better; dynamic disks save space during setup.

Networking choices — NAT, Bridged, Host-Only — affect whether the VM can reach the internet, whether other devices can see the VM, and whether the host and VM can communicate directly. Most beginner setups use NAT and never think about it again. More advanced setups (running servers, testing network configurations) require deliberate network design.

Different Setups, Different Outcomes

A developer on a Linux workstation with 64GB of RAM spinning up a headless Ubuntu server VM has almost nothing in common — procedurally or practically — with a Windows 11 Home user trying to test an old application in an XP environment. Both are "creating a VM," but the tools, constraints, and results are entirely different.

The platform you're on, the resources available, the OS you want to run, and what you need the VM to actually do are all factors that shape every decision in the process — from which hypervisor makes sense to how much RAM to allocate to whether the whole thing is even practical on your current machine.