The Proxmox installer is quick and friendly — and it erases the complete target disk without a dual-boot option or an undo button. That single fact is responsible for most Proxmox disasters. This short guide covers exactly what gets wiped, the rescue checklist to run first, and the three installer decisions that actually matter.
Every week someone discovers the whole-disk wipe after clicking through it. The information is not hidden — the installer says it plainly — but excitement is a powerful skip button. So here it is with no fine print: one disk, completely erased, no exceptions. Everything below exists to make sure that never costs you anything.
The Proxmox installer does not offer partitions to keep, a dual-boot option, or an 'install alongside Windows' mode. You select one target disk, and the entire disk is erased and repartitioned for Proxmox: the system itself, a storage area for ISO files and templates, and an LVM-thin pool for your virtual disks. 'Whole disk' also means the whole disk — a second partition with your data on the same physical drive is deleted just as completely as the Windows partition.
Five minutes here is the whole difference between an exciting project and a very bad evening. There is no step 2 if this is skipped — after the install, recovery software has nothing meaningful left to recover from a freshly partitioned, actively used disk.
The graphical installer is short. Most screens are harmless defaults — country, time zone, keyboard. Three decisions deserve your attention: the target disk (double-check the size and model shown match the drive you intend to sacrifice; under Options you can also limit how much space the system itself takes), the root password (this is the master login for the whole host — make it strong and store it where you store other infrastructure passwords), and the network settings. Give the host a static IP outside your router's DHCP range, the correct gateway and a DNS server. A server that changes address after every power cut will train your whole household to hate it.
A successful install ends quietly: the PC reboots into a black text console showing a login prompt and the management address, https://your-ip:8006. No desktop appears, ever — that is correct, not a failed install. From another machine's browser you log in as root, click through the normal self-signed certificate warning, and you are standing in your new server's control room. Only now is it safe to say the sentence out loud: the old PC is gone, and in its place there is a hypervisor.
See the full Proxmox installation and first VM creation, live and step by step.
▶️ Watch Full VideoNo. The Proxmox installer takes the entire target disk. If you want both, the sensible arrangement is the other way around: install Proxmox as the host and run Windows as a virtual machine inside it.
No — only the disk you select as the installation target is erased. But be certain which one you selected: the installer identifies disks by model and capacity. Temporarily disconnecting the disk you want to preserve is the foolproof method.
Realistically, no. The disk is repartitioned and immediately begins storing new data. Treat anything not copied off beforehand as permanently gone — which is exactly why the rescue checklist comes before the installer, not after.