Windows Server 2025 offers significant upgrades in performance, security, and cloud integration, along with a more refined and modern interface. Installing it on Proxmox VE provides a convenient way to explore its new capabilities, experiment with remote management tools, and prepare for future production environments. Additionally, the 180-day evaluation version allows you to test and familiarize yourself with the system without worrying about licensing restrictions.
This guide walks you through the entire process of how to install Windows Server 2025 inside Proxmox VE 8 – from preparing the ISO files to installing VirtIO drivers, enabling RDP, and finalizing your server configuration.
Prerequisites
Before starting, make sure you have the following ready:
- First, make sure Proxmox VE 8.x is up and running on your machine.
- Windows Server 2025 ISO (evaluation version from the official Microsoft website)
- VirtIO drivers ISO (from Fedora or Red Hat)
- At least 50 GB of free storage for the virtual machine
- A working network bridge on Proxmox (e.g., vmbr0)
- You should have familiarity with the Proxmox web interface (GUI)
Installing Windows Server 2025 on Proxmox VE 8
Step 1: Create a New Virtual Machine
Log in to your Proxmox Web UI. Now, navigate to your Proxmox node and click ‘Create VM’. Give the VM a name, such as windows2025, and choose a unique VM ID.
On the OS tab, select Microsoft Windows and attach the Windows Server 2025 ISO as the primary CD/DVD.
Add another CD/DVD drive and attach the VirtIO ISO – this provides storage and network drivers during setup.
Step 2: Configure System Settings
In the System tab, set the following:
- Machine: q35
- BIOS: SeaBIOS (recommended for compatibility; switch to OVMF if you need UEFI or Secure Boot)
- TPM: Enable (optional, required for some security features)
- QEMU Guest Agent: Enable (for smooth shutdowns and host-guest communication)
- SCSI Controller: VirtIO SCSI single
Important Note: If you plan to use Secure Boot, change BIOS to OVMF (UEFI) before installation.
Step 3: Set VM Resources (Disk, CPU, Memory)
Once you’ve created the virtual machine in Proxmox, the next step is to allocate the appropriate system resources to ensure your Windows Server 2025 installation runs smoothly. These settings determine how your VM will perform, so it’s important to configure them carefully.
1. Disk Configuration
When setting up the virtual hard disk, use the following options for optimal performance and flexibility:
- Bus/Device: Use VirtIO Block (or VirtIO SCSI) for optimal I/O performance through efficient communication with the Proxmox host.
- Disk Size: Allocate at least 50 GB, or more based on your workload (e.g., file server, domain controller, testing).
- Format: Choose qcow2 for snapshot flexibility, or raw for better performance.
- Cache Mode: Set to Writeback for improved speed with safe data handling.
2. CPU Configuration
Assign CPU resources to your VM:
- Sockets/Cores: Assign 1 socket and 2 cores — suitable for testing or light workloads; increase cores for production use.
- CPU Type: Choose a host to leverage the Proxmox system’s full CPU features for better performance and compatibility.
3. Memory (RAM) Configuration
Finally, configure the memory allocation for your VM:
- Memory Size: Assign at least 4 GB of RAM. This is the recommended minimum for Windows Server 2025 to run comfortably.
- If you’re using the server for active roles (such as running a database, Active Directory, or IIS), consider increasing the memory to 8 GB or more.
- Make sure not to overcommit memory unless your Proxmox node has swap space and enough physical RAM to support multiple VMs.
Step 4: Configure Networking
Set the network model to VirtIO (paravirtualized) for optimal network performance and low overhead.
Under the Bridge option, choose vmbr0 — this is the default network bridge in Proxmox that connects your virtual machine to the host’s physical network interface.
If you’ve configured a custom bridge for specific network segmentation or VLANs, select that instead. You can leave the remaining network settings at their default values unless your setup requires specific adjustments.
Step 5: Create and Start the VM
Tick “Start after created” if you want it to boot immediately. Click Finish to complete the setup.
Your VM should now boot into the Windows Server 2025 installation screen.
Step 6: Installing Windows Server 2025
First, select your language, time zone, and keyboard layout.
Select Windows Server 2025 Standard Evaluation (Desktop Experience).
Accept the license terms and choose Custom: Install Windows only.
At this point, you’ll notice no drives are detected. Don’t worry, this issue will be fixed in the next step.
Step 7: Load VirtIO Drivers (Storage & Network)
- Click “Load Driver” when no disk appears during setup.
- Browse to the VirtIO ISO (usually mounted as D:).
- Go to D:\amd64\2k25\.
- Select Red Hat VirtIO SCSI Controller (viostor.inf) and click Next.
- The 50 GB virtual disk should now appear, ready for installation.
If you also want to load network drivers, select netkvm.inf from the same folder.
Step 8: Complete the Installation
Select the partition and format the unallocated space.
Proceed with installation — Windows will copy files and reboot.
Once done, set the Administrator password and log in.
Step 9: Install VirtIO Guest Tools
To improve VM performance and enable features like ballooning and graceful shutdowns:
- Mount the VirtIO ISO again (if needed).
- Run: virtio-win-guest-tools.exe
Follow the prompts and install all recommended components. Reboot the VM.
After that, remove the external drive:
Congratulation! Windows Server 2025 has been installed successfully on Promox.
Conclusion
We demonstrated in this guide how to install Windows Server 2025 inside Proxmox VE 8 using VirtIO drivers for maximum performance. With the QEMU Guest Agent and VirtIO tools, your VM will run smoothly and integrate tightly with your Proxmox environment. I hope you enjoyed this tutorial. Thanks!
