Windows 10 on VirtualBox: Setup Guide

This guide walks you through installing Windows 10 as a virtual machine in Oracle VirtualBox, letting you run Windows alongside your current operating system without partitioning your drive. You’ll download a Windows 10 ISO, create a VM, configure settings, and complete the installation. Before starting, ensure your CPU supports hardware virtualization (VT-x/AMD-V) and that you have at least 25 GB of free disk space and 4 GB of RAM to dedicate to the VM.

What You’ll Need

VirtualBox – Download and install the latest version from virtualbox.org (Windows, macOS, Linux, or Solaris hosts are supported).
Windows 10 ISO – Get the official ISO from Microsoft’s download page. You can use the Media Creation Tool to download the ISO directly.
Windows 10 license – You can install and use Windows 10 without a key for a while, but activating it requires a valid license.
Hardware virtualization enabled – Check your BIOS/UEFI settings; VT-x (Intel) or AMD-V must be turned on. Most modern PCs have it enabled by default.
Sufficient RAM and disk space – At least 4 GB of RAM for the VM (more is better) and about 25-30 GB of free hard drive space for the virtual disk.

Step-by-Step

Download VirtualBox – Go to virtualbox.org, download the installer for your host OS, and run it. Follow the default installation prompts. If you’re on Windows, allow the driver installation when prompted.
Download Windows 10 ISO – Visit Microsoft’s software download page. Choose “Download tool now� and run the Media Creation Tool. Accept the license terms, select “Create installation media for another PC,� choose language and edition, then select “ISO file.� Save the ISO to a location you can find.
Create a New Virtual Machine – Open VirtualBox. Click “New� (or press Ctrl+N). Name the VM (e.g., “Windows 10�). VirtualBox will auto-detect the type as “Microsoft Windows� and version as “Windows 10 (64-bit)� if you have a 64-bit ISO. If not, adjust manually. Click “Next.�
Allocate Memory – Set the RAM size. The recommended minimum is 2048 MB (2 GB), but 4096 MB (4 GB) is better for smoother performance. Do not exceed the green zone (usually half your host RAM). Click “Next.�
Create a Virtual Hard Disk – Choose “Create a virtual hard disk now� and click “Create.� Select “VDI (VirtualBox Disk Image)� as the file type. Choose “Dynamically allocated� so the disk grows as needed. Set the size to at least 25 GB (50 GB is safer for updates and applications). Click “Create.�
Configure VM Settings (Optional but Recommended) – Select the VM and click “Settings.� Under “System,� ensure “Enable EFI� is unchecked (unless you specifically need UEFI). Under “Processor,� give the VM 2 CPU cores if your host has 4 or more. Under “Display,� increase Video Memory to 128 MB and enable “3D Acceleration� if you want better graphics. Under “Storage,� click the empty optical drive and then the disk icon to “Choose a disk file,� selecting your Windows 10 ISO.
Start the Virtual Machine – Click “Start.� The VM will boot from the ISO. You’ll see the Windows logo and the setup screen.
Install Windows 10 – Select your language, time, and keyboard preferences, then click “Next.� Click “Install now.� Enter a product key if you have one; otherwise click “I don’t have a product key� (you can activate later). Choose the edition (usually “Windows 10 Pro� or “Home�) and accept the license terms. Select “Custom: Install Windows only (advanced).�
Select the Virtual Disk – You’ll see an unallocated space (the virtual disk). Select it and click “Next.� Windows will begin copying files. The VM will restart a few times; when it does, you may see a message about “Press any key to boot from CD or DVD.� Do NOT press any key, so it boots from the hard disk.
Complete Setup – After the final restart, Windows will ask for region, keyboard layout, and account creation. You can use a Microsoft account or create a local account (choose “Offline account� if you prefer). Set a password and security questions. Choose privacy settings (you can turn most off). Wait for Windows to finalize settings and reach the desktop.
Install VirtualBox Guest Additions – Once on the desktop, go to the “Devices� menu in the VM window and select “Insert Guest Additions CD image.� Open File Explorer, find the CD drive (D:), and run “VBoxWindowsAdditions.exe.� Follow the installation, allow the driver install, and reboot the VM. This enables better screen resolution, mouse integration, clipboard sharing, and drag-and-drop.

Common Mistakes

Not enabling virtualization in BIOS – If you get an error like “VT-x is not available,� you need to enter your BIOS/UEFI and enable Intel VT-x or AMD-V.
Allocating too little RAM – 2 GB works but is sluggish. 4 GB is the sweet spot for basic use.
Choosing a fixed-size disk – Fixed disks take up all the space immediately and take longer to create. Dynamically allocated is more flexible.
Forgetting Guest Additions – Without them, the VM runs at low resolution and lacks clipboard sharing.
Pressing a key during reboot – This can cause the installer to restart instead of booting from the hard disk. Just let it sit.

Tips

Use 64-bit Windows 10 – If your CPU supports it, choose the 64-bit version for better performance and compatibility.
Enable nested paging – In VM settings under System > Acceleration, ensure “Enable VT-x/AMD-V� and “Enable Nested Paging� are checked for better performance.
Snapshot before major changes – Take a snapshot of the VM after a clean install. If something goes wrong, you can revert in seconds.
Set up shared folders – With Guest Additions, you can share a folder between host and guest for easy file transfer.
Adjust video memory – Increase to 128 MB to avoid display glitches, especially if you enable 3D acceleration.

Troubleshooting

“VT-x is not available� error – Restart your computer, enter BIOS/UEFI (usually by pressing F2, Del, or Esc during boot), find “Intel Virtualization Technology� or “SVM Mode,� enable it, save and exit.
Black screen or no display after starting VM – Try increasing video memory to 128 MB, disable 3D acceleration, or switch the graphics controller to “VBoxSVGA� in Display settings.
Windows installation fails or freezes – Ensure you have enough free disk space on the host. Also, try disabling “Enable EFI� in System settings if you had it on.
Mouse gets stuck inside the VM – Press the right Ctrl key (or Host key) to release the mouse. Install Guest Additions to fix this permanently.
VM is very slow – Allocate more CPU cores (if available), increase RAM, and make sure you’re not running other heavy applications on the host.
“No bootable medium found� – The ISO may not be attached. Go to Settings > Storage, click the optical drive, and select your ISO file.

Frequently Asked Questions

Can I run Windows 10 on VirtualBox for free?

Yes, VirtualBox is free, and you can install Windows 10 without entering a product key. It will run with a watermark and limited personalization until you activate it with a valid license.

How much RAM should I give the Windows 10 VM?

At least 2 GB, but 4 GB is recommended for smooth performance. If your host has 8 GB or more, you can allocate 4 GB without issue.

Will Windows 10 run fast in a VM?

It depends on your hardware. With an SSD, a modern CPU, and enough RAM, Windows 10 can run quite well for basic tasks. It won’t be as fast as native, but it’s perfectly usable.

Can I use a Windows 10 ISO from the Media Creation Tool?

Yes, the Media Creation Tool can download the ISO directly. Just select “Create installation media for another PC� and choose “ISO file.�

Do I need to activate Windows 10 in the VM?

No, you can use it without activation, but you’ll see a watermark and can’t change personalization settings. You can activate later with a valid key.

Can I copy files between the host and the VM?

Yes, after installing Guest Additions, you can enable drag-and-drop and shared clipboard in VM settings, or set up shared folders.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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