Can You Run a Windows VM on an EXT4 Drive? Type 1 vs Type 2 Hypervisors Explained
The short answer: EXT4 is not a problem
Your hard drive’s filesystem format has no effect on what guest operating systems you can run in VirtualBox. Windows will install and run fine inside a VM on a Linux Mint machine with an EXT4 drive. The two filesystems operate at completely different layers and never interact.
Why the filesystem doesn’t matter
VirtualBox doesn’t give Windows direct access to your physical drive. Instead, it creates a disk image file — typically a .vdi file — stored on your EXT4 drive like any other file. When Windows runs inside the VM, it sees a virtual hard disk backed by that file. Windows formats that virtual disk as NTFS during installation. Your host Linux system keeps its EXT4. Neither OS touches the other’s filesystem.
A useful mental model: a ZIP file can contain a Word document even if the drive holding the ZIP uses EXT4. The container format and the content format are independent. A VM disk image is just a large container.
VirtualBox is a Type 2 hypervisor
Before getting into what a Type 1 hypervisor is, it helps to know where VirtualBox actually sits. VirtualBox is a Type 2 hypervisor, also called a hosted hypervisor. It runs as an application inside your host OS — Linux Mint, in this case. When you start a VM, VirtualBox asks Linux for CPU time, memory, and disk access, then presents a virtual hardware environment to the guest. Windows boots inside that environment without any direct contact with your physical hardware.
Type 2 needs a host OS to start. If Linux isn’t running, VirtualBox can’t run either.
What makes a Type 1 hypervisor different
A Type 1 hypervisor, sometimes called a bare-metal hypervisor, runs directly on the physical hardware. There’s no conventional host OS between it and the CPU. Examples include VMware ESXi, Proxmox VE, and Microsoft Hyper-V in its server configuration. The hypervisor is effectively the operating system, and all VMs run as guests on top of it.
The advantage is efficiency and isolation. Without a general-purpose OS consuming resources below it, more of the hardware goes to the VMs. Data centers run Type 1 hypervisors almost exclusively for this reason.
Hypervisor vs. virtual machine
A hypervisor is the software that creates and manages virtual machines. A virtual machine is the guest environment the hypervisor produces. They’re separate things. Think of the hypervisor as the platform and the VM as an instance running on that platform. VirtualBox is the hypervisor; the Windows session you launch inside VirtualBox is the VM. One creates, one runs.
Can you run a Type 1 hypervisor alongside Linux?
This is worth being precise about, because the answer depends on what you mean.
A traditional bare-metal hypervisor like VMware ESXi replaces your OS entirely during installation. You can’t dual-boot ESXi and Linux on the same machine the way you’d dual-boot Windows and Linux. If you want Linux available under ESXi, you’d run a Linux VM inside ESXi — not Linux directly on the bare metal.
Proxmox VE is a popular choice for home lab users. It’s a Debian-based Linux distribution with KVM and container support built on top. From a setup perspective it feels like installing Linux, then gaining hypervisor capabilities. But the right mental model is: Proxmox is the OS, and everything else runs as a VM or container under it.
KVM: where the line blurs
The Linux kernel includes a module called KVM (Kernel-based Virtual Machine). When KVM is active, the kernel gains Type 1 characteristics — it can schedule VM workloads directly using hardware virtualization extensions like Intel VT-x or AMD-V. Tools like QEMU and libvirt manage those VMs from the command line, or through a GUI like virt-manager.
On a standard Linux Mint desktop with KVM enabled, you technically have Type 1 hypervisor behavior running alongside your normal desktop session. This is the well-known gray area in the Type 1 vs Type 2 classification. VirtualBox is the simpler path for a class project; KVM-based setups are more powerful but require considerably more configuration.
Disk formatting for a bare-metal setup
If you wanted to put Proxmox on the same physical machine as Linux, the typical approach is to install Proxmox and let it take the whole drive, then run Linux as a VM under Proxmox. Running Proxmox and Linux on separate partitions side by side isn’t how bare-metal hypervisors are designed to work. Proxmox handles its own disk partitioning at install time.
Windows VMs under Proxmox still use NTFS inside their virtual disks. Same principle as VirtualBox: the host filesystem and the guest filesystem are always separate concerns.