Windows Server 2025 Datacenter: Download, Install and Activation Guide

This guide is for Windows Server 2025 Datacenter. It covers a clean install on a physical host or virtual machine, converting an evaluation or Standard build to Datacenter, activation, and activating the guest VMs afterwards.

Before you start

• Requirements: 1.4 GHz 64-bit processor with virtualisation extensions, 512 MB RAM minimum (plan for far more on a Hyper-V host), 32 GB storage, gigabit network adapter. UEFI with Secure Boot and TPM 2.0 are recommended.
• Have your 25-character Windows Server 2025 Datacenter key ready.

Step 1: Download the installation media

Use the download link in your delivery email. If it points to Microsoft's Evaluation Center, that is normal: the evaluation ISO is the same media, and Step 3 converts it to the full edition.

1. Download the Windows Server 2025 ISO.
2. For a physical host, write it to a USB drive with Rufus. For a VM, mount the ISO in your hypervisor.

Step 2: Install Windows Server 2025

1. Boot from the media and select Install Windows Server.
2. At the product key screen, enter your key if accepted, or choose I don't have a product key.
3. Select Windows Server 2025 Datacenter (Desktop Experience) for a graphical interface, or Windows Server 2025 Datacenter for Server Core.
4. Accept the licence terms, choose Custom, select the drive and continue.
5. Set the Administrator password when prompted.

Step 3: Convert to full Datacenter

Skip this if the installer accepted your key in Step 2. It applies to an evaluation build, and also to an existing Standard install you want to move up to Datacenter without reinstalling.

1. Open PowerShell as Administrator.
2. Check the edition: DISM /Online /Get-CurrentEdition. You will see ServerDatacenterEval, ServerStandardEval or ServerStandard.
3. Run the conversion with your key:
   DISM /Online /Set-Edition:ServerDatacenter /ProductKey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX /AcceptEula
4. The server restarts, which can take several minutes.

Step 4: Activate the host

1. Open Settings > System > Activation. The DISM step often activates it directly.
2. If not, select Change product key, enter the key and select Activate.
3. Or from an elevated prompt: slmgr /ipk XXXXX-XXXXX-XXXXX-XXXXX-XXXXX, then slmgr /ato. Confirm with slmgr /xpr.

Step 5: Activate guest VMs with AVMA

Datacenter includes Automatic Virtual Machine Activation. Windows Server guests on this activated host activate against the host, with no internet and no extra keys.

1. Install the Hyper-V role and create your VMs as normal.
2. Inside each Windows Server guest, run slmgr /ipk with the matching AVMA key from Microsoft's AVMA documentation, then slmgr /ato.
3. AVMA works for Server 2025, 2022, 2019, 2016 and 2012 R2 guests. It requires Hyper-V; it does not work on VMware or Proxmox.

Windows Server 2025 Datacenter specific problems

Key rejected on an evaluation install

Go back to Step 3. Evaluation builds only accept a key through DISM /Set-Edition.

Guest VM will not activate with AVMA

Check the host itself is activated, the guest is on Hyper-V, and the Data Exchange integration service is enabled in the VM settings.

Error 0xC004F074, activation server unreachable

The host needs outbound HTTPS (port 443). Check firewall and proxy, or use phone activation if your delivery email says your key supports it.

Need help?

Do not keep retrying a rejected key. Screenshot the error and the output of DISM /Online /Get-CurrentEdition, then contact support with your order number. Server 2025 is in mainstream support until November 2029, and your purchase is covered by our 6-month licence warranty.