This windows server 2025 upgrade guide is written for system administrators planning a migration from Windows Server 2016 or 2019 in production environments where downtime must be minimised and the upgrade path must be validated before execution.
Windows Server 2025, released by Microsoft in November 2024, is the first Windows Server LTSC release since Windows Server 2022. It introduces significant security, storage, and networking improvements — including built-in SMB over QUIC, hotpatching without reboots (in preview for on-premises), and enhanced Active Directory capabilities.
This windows server 2025 upgrade guide covers every step: system requirements, supported upgrade paths, pre-upgrade checklist, in-place upgrade procedure, Active Directory schema upgrade, post-upgrade validation, and the licensing considerations that affect your budget planning.
Table of Contents
- What is New in Windows Server 2025
- Windows Server 2025 System Requirements
- Supported Upgrade Paths
- Windows Server 2025 Licensing Cost
- Windows Server 2025 vs 2022 Comparison
- Pre-Upgrade Checklist
- In-Place Upgrade Step by Step
- Active Directory Schema Upgrade
- Hyper-V Improvements in Windows Server 2025
- Post-Upgrade Validation
- Troubleshooting Common Upgrade Issues
- Frequently Asked Questions
- Conclusion
What is New in Windows Server 2025
Understanding the new features is the first step in any windows server 2025 upgrade guide — it defines whether the upgrade delivers immediate value for your specific workloads.
Security Improvements
- Hotpatching (on-premises preview): Apply security patches without rebooting the server. Previously available only for Azure VMs, on-premises hotpatching dramatically reduces patching downtime for production workloads
- Credential Guard enabled by default: Protects NTLM and Kerberos credentials from extraction attacks with no manual configuration required on new deployments
- Delegation Signer (DS) records for DNSSEC: Simplified DNSSEC deployment with automatic DS record management
- Windows Defender Application Control improvements: Expanded policy support for application allowlisting in enterprise environments
Storage and Networking
- SMB over QUIC (all editions): Previously an Azure-only feature, SMB over QUIC is now available on-premises — allowing secure SMB file access over the internet without a VPN tunnel
- Storage Replica compression: Block-level replication now supports data compression, reducing bandwidth requirements for stretched cluster replication by 40–60%
- NVMe over Fabrics (NVMe-oF): Native NVMe-oF support for high-performance storage networking in HCI and SAN environments
- SMB 3.1.1 encryption default upgraded: AES-256-GCM is now the default for SMB connections, stronger than the AES-128 default in Windows Server 2022
Active Directory
- New forest and domain functional level (2025): Introduces improved Kerberos armoring and authentication policy improvements
- 26-character NETBIOS name support: Removes the legacy 15-character NETBIOS name limit for new domains
- DC-side time zone support: Domain controllers can now be configured with location-aware time zones
Windows Server 2025 System Requirements
Verify hardware compatibility before starting this windows server 2025 upgrade guide. Hardware that does not meet minimum requirements fails at the upgrade pre-check stage — not during the upgrade itself, which wastes time.
| Component | Minimum | Recommended (Production) |
|---|---|---|
| CPU | 1.4 GHz, 64-bit, x64 compatible | 2 GHz or faster, multi-core |
| RAM | 512 MB (Server Core), 2 GB (Desktop Experience) | 16 GB+ for production role servers |
| Storage | 32 GB | 100 GB+ OS drive (SSD recommended) |
| Network | Gigabit Ethernet adapter | 10 GbE for file server and Hyper-V hosts |
| Firmware | UEFI (required for Secure Boot) | UEFI with TPM 2.0 |
| TPM | TPM 2.0 (required for Credential Guard) | TPM 2.0 |
Servers without TPM 2.0 can still install Windows Server 2025 but Credential Guard will be unavailable — a significant security regression for Active Directory domain controllers, as noted in the official Windows Server 2025 hardware requirements documentation.
Supported Upgrade Paths
This is the most critical section of any windows server 2025 upgrade guide — the upgrade path determines whether you can perform an in-place upgrade or must plan a full server migration.
| Current Version | Direct Upgrade to 2025 | Notes |
|---|---|---|
| Windows Server 2022 | Yes — supported | Straightforward in-place upgrade |
| Windows Server 2019 | Yes — supported | Direct in-place upgrade supported |
| Windows Server 2016 | Yes — supported | Direct upgrade; verify driver compatibility first |
| Windows Server 2012 R2 | No — not supported | Must migrate to 2019 first, then upgrade to 2025 |
| Windows Server 2012 | No — not supported | Two-step migration required |
Windows Server 2025 Licensing Cost
Licensing planning is essential before starting this windows server 2025 upgrade guide in production. Unexpected licensing costs are one of the most common reasons upgrade projects get delayed after planning has already started.
Windows Server 2025 uses the same core-based licensing model as previous versions. Key pricing:
- Windows Server 2025 Standard: Approximately $1,069 per 16-core licence — includes rights to run 2 Hyper-V VMs
- Windows Server 2025 Datacenter: Approximately $6,155 per 16-core licence — includes unlimited Hyper-V VMs
- Windows Server 2025 Essentials: Approximately $501 — for organisations up to 25 users / 50 devices
Customers with active Software Assurance on Windows Server 2022 licences are entitled to upgrade to Windows Server 2025 at no additional licence cost. For organisations running Hyper-V with multiple VMs per host, Datacenter edition is almost always the correct economic choice at scale — see our Hyper-V setup guide for host capacity planning that directly impacts your edition decision.
Windows Server 2025 vs 2022 Comparison
| Feature | Windows Server 2022 | Windows Server 2025 |
|---|---|---|
| Hotpatching | Azure VMs only | On-premises (preview) + Azure |
| SMB over QUIC | Azure Edition only | All editions |
| AD Functional Level | 2022 | 2025 (new) |
| Credential Guard | Optional, manual enable | Enabled by default |
| SMB Encryption Default | AES-128-GCM | AES-256-GCM |
| NVMe-oF Support | No | Yes |
| Mainstream Support End | October 2026 | October 2029 |
Pre-Upgrade Checklist
Completing this checklist before starting the in-place upgrade is the difference between a smooth 90-minute maintenance window and a 6-hour recovery operation. Every item in this windows server 2025 upgrade guide pre-checklist is based on a real incident that skipping it caused.
- ✅ Full system backup, verified restore tested — not just a backup that has never been tested
- ✅ Hardware compatibility check — run the Windows Server 2025 compatibility check tool from installation media
- ✅ Driver compatibility — verify all critical drivers (storage controllers, NIC) for Windows Server 2025 support from the vendor
- ✅ Application compatibility — check all installed applications against their vendor’s Windows Server 2025 support matrix
- ✅ Minimum 20 GB free on OS volume — upgrade files require this during the process
- ✅ Windows Update fully current — install all available updates for the current OS version before upgrading
- ✅ Remove third-party security software — AV and EDR agents frequently block in-place upgrades; uninstall before, reinstall after
- ✅ Document current server roles — list all installed Windows roles and features; verify each is supported on Windows Server 2025
- ✅ For Domain Controllers: verify SYSVOL replication health and ensure at least one other DC is operational before upgrading any DC
- ✅ Test upgrade on non-production first — complete this entire windows server 2025 upgrade guide on a test server before touching production
In-Place Upgrade Step by Step
This is the core of the windows server 2025 upgrade guide. An in-place upgrade preserves all installed roles, settings, applications, and data while replacing the OS version.
Phase 1: Mount the Windows Server 2025 Installation Media
Download the Windows Server 2025 ISO from the Microsoft Volume Licensing Service Center (VLSC) or Visual Studio Subscriptions, or mount it directly on the server. Run setup.exe from the mounted media.
Phase 2: Setup Initial Options
When Setup launches, select “Download updates, drivers and optional features (recommended)” to ensure the latest servicing stack is applied during upgrade. Accept the licence terms.
Phase 3: Select Edition
Choose the edition matching your current licence: Standard or Datacenter. Select Windows Server 2025 Desktop Experience or Server Core based on your current configuration. Switching from Desktop Experience to Server Core during an in-place upgrade is not supported — that requires a clean install.
Phase 4: Choose Upgrade Option
Select “Upgrade: Install Windows and keep files, settings, and applications”. This is the critical selection in this windows server 2025 upgrade guide. Selecting “Custom: Install Windows only (advanced)” will wipe the drive.
Phase 5: Upgrade Executes
The upgrade process takes 45–120 minutes depending on hardware speed and the number of installed roles. The server reboots multiple times. Do not interrupt the process. Messages like “Restoring your previous version of Windows” during certain phases are normal and do not indicate a failure.
Phase 6: Post-Upgrade First Boot
After the final reboot, log in with the same administrator credentials. Open Server Manager and verify all roles show as installed and running. This confirms the windows server 2025 upgrade guide in-place process completed successfully.
Active Directory Schema Upgrade
If any server in your environment is a Domain Controller, the Active Directory schema must be updated before promoting a Windows Server 2025 DC. This section of the windows server 2025 upgrade guide applies to all environments with Active Directory Domain Services.
The schema upgrade is a one-way operation. Always back up Active Directory and the System State before proceeding. Run these steps from a machine with the AD DS tools installed, using an account that is a member of Schema Admins and Enterprise Admins.
Mount the Windows Server 2025 media and run the schema preparation from an elevated command prompt in the supportadprep folder on the installation media:
- adprep /forestprep — extends the Active Directory schema for the entire forest (run once per forest)
- adprep /domainprep — updates the domain infrastructure (run on the Infrastructure Master of each domain)
- adprep /domainprep /gpprep — updates Group Policy infrastructure
Verify schema version after forestprep: confirm the schema version matches Windows Server 2025 (schema version 91). After the schema update replicates to all DCs, you can promote a Windows Server 2025 DC and eventually raise the Domain and Forest Functional Level to Windows Server 2025.
Hyper-V Improvements in Windows Server 2025
For environments running Hyper-V, this windows server 2025 upgrade guide section covers the specific virtualisation improvements that justify the upgrade for VM hosts:
- Generation 2 VM Secure Boot improvements: Enhanced support for a wider range of Linux distributions without manual policy changes
- Virtual machine GPU partitioning (vGPU): Improved GPU-P support for AI and graphics workloads across multiple VMs
- Live migration improvements: Reduced live migration time for large-memory VMs through improved compression
- Nested virtualisation improvements: Better performance for nested Hyper-V scenarios used in dev/test environments
For detailed Hyper-V configuration on Windows Server 2025, this windows server 2025 upgrade guide works alongside our complete Hyper-V setup guide which covers virtual switch configuration, VM creation, and storage best practices applicable to Windows Server 2025. If you are running domain controllers after this upgrade, also see our guide on fixing RDP issues on Windows Server — a common post-upgrade issue caused by changed NLA defaults.
Post-Upgrade Validation
After completing the in-place upgrade steps in this windows server 2025 upgrade guide, validate these items before declaring the upgrade successful:
- Open Server Manager — all previously installed roles should show as installed and running
- Verify all services that were running before the upgrade are running after
- Test all application connectivity — web services, database connections, file shares
- For Domain Controllers: run dcdiag /test:all and verify no failures
- Check Windows Event Viewer System and Application logs for new errors in the first 30 minutes
- Confirm Windows Update shows the correct OS version: Windows Server 2025
- Verify network connectivity and DNS resolution are functioning correctly
- For Hyper-V hosts: verify all VMs start correctly and have network connectivity
Troubleshooting Common Upgrade Issues
Issue 1: Upgrade Fails at Compatibility Check
Symptoms: Setup exits immediately with a compatibility error before the upgrade begins.
Root cause: Missing TPM 2.0, insufficient disk space, or an incompatible driver or application flagged by the compatibility checker.
Review the SetupDiag tool output and the $WINDOWS.~BTSourcesPantherCompatData.xml file — it lists every specific reason the compatibility check failed with remediation steps for each item.
Issue 2: Upgrade Rolls Back to Previous OS
Symptoms: Upgrade appears to progress through multiple reboots then restores the previous OS version.
Root cause: An incompatible driver, application, or Windows feature blocks the upgrade at the commit phase. Most commonly caused by leaving antivirus software installed during the upgrade.
Review C:WindowsPanthersetuperr.log for the specific failure. Uninstall the flagged application or driver, then retry the upgrade.
Issue 3: Active Directory Replication Fails After DC Upgrade
Symptoms: After upgrading a DC’s OS, Active Directory replication fails or the DC shows as failed in Active Directory Sites and Services.
Root cause: Schema was not updated before the upgrade, or replication was already failing before the upgrade began.
Run repadmin /showrepl to check replication status. Run dcdiag /test:replications to identify specific replication errors. Verify adprep was run successfully before the upgrade.
Issue 4: Applications Fail After Upgrade
Symptoms: Applications that worked on Server 2016/2019 fail to start or throw errors on Windows Server 2025.
Root cause: Application compatibility issues, particularly with applications relying on deprecated Windows features or specific TLS versions. Windows Server 2025 disables TLS 1.0 and 1.1 by default — applications requiring these legacy protocols will fail.
Frequently Asked Questions
Can I upgrade directly from Windows Server 2016 to Windows Server 2025?
Yes — according to this windows server 2025 upgrade guide and Microsoft’s official upgrade support matrix, direct in-place upgrade from Windows Server 2016 to Windows Server 2025 is supported. Verify hardware compatibility, particularly TPM 2.0 and driver support, before starting. Complete driver and application compatibility checks first as some third-party applications may need updates to support Windows Server 2025.
What are the new features in Windows Server 2025?
Windows Server 2025 introduces hotpatching for on-premises servers (in preview), SMB over QUIC available on all editions, Credential Guard enabled by default, Storage Replica with compression, NVMe over Fabrics support, a new Windows Server 2025 Active Directory functional level, and AES-256-GCM as the default SMB encryption standard. These represent meaningful security and storage improvements over Windows Server 2022 and are the primary reason to follow this windows server 2025 upgrade guide now rather than waiting.
What are the hardware requirements for Windows Server 2025?
Windows Server 2025 requires a 64-bit CPU at minimum 1.4 GHz, 512 MB RAM (Server Core) or 2 GB (Desktop Experience), 32 GB storage minimum, and UEFI with TPM 2.0. TPM 2.0 is required for Credential Guard which is enabled by default. Servers without TPM 2.0 can still install Windows Server 2025 but lose the default security benefit. A 10 GbE NIC is recommended for Hyper-V hosts and file servers.
How long does a Windows Server upgrade take?
An in-place upgrade from Windows Server 2016 or 2019 to Windows Server 2025 takes between 45 and 120 minutes depending on hardware speed, the number of installed roles, and whether drivers need to be updated during the process. Plan a 3-hour maintenance window to include pre-upgrade validation, the upgrade itself, and post-upgrade testing before declaring the window closed.
Is Windows Server 2025 free for existing license holders?
Windows Server 2025 is not free unless you have active Software Assurance on your current Windows Server licence. Software Assurance entitles you to upgrade to new versions at no additional licence cost. Without Software Assurance, you must purchase a new Windows Server 2025 licence. Standard edition starts at approximately $1,069 per 16-core licence pack.
Conclusion: Your Windows Server 2025 Upgrade Guide Summary
This windows server 2025 upgrade guide has covered every element needed for a successful migration from Windows Server 2016 or 2019: new features, system requirements, supported upgrade paths, licensing costs, the pre-upgrade checklist, in-place upgrade procedure, Active Directory schema upgrade, and post-upgrade validation.
Key takeaways from this windows server 2025 upgrade guide:
- Direct upgrade from 2016 is supported: No intermediate version required for most environments
- TPM 2.0 matters: Without it, Credential Guard (enabled by default) is unavailable — a security regression for DCs
- Software Assurance holders upgrade free: Check your SA status before purchasing new licences
- Test on non-production first: Every step in this windows server 2025 upgrade guide should be completed on a test server before production
- SMB over QUIC and hotpatching are the headline features: Both deliver immediate operational value for organisations with remote access and patching compliance requirements
Related reading on navedalam.com:
- Hyper-V Setup Guide — configure Hyper-V on Windows Server 2025 after your upgrade
- RDP Not Working on Windows Server — fix common RDP issues that appear after OS upgrades
- Azure VPN Gateway Configuration — extend your upgraded Windows Server environment into Azure hybrid networking
- Azure Cost Optimization Guide — reduce Azure costs if you are migrating workloads to Azure after this upgrade
- Remote IT Support Services — expert help with Windows Server upgrades and migrations
External references:
- What’s New in Windows Server 2025 — Microsoft Learn
- Windows Server Upgrade Overview — Microsoft Documentation
- NIST Guide to Enterprise Patch Management Planning (SP 800-40)
Need Expert Help with Your Windows Server 2025 Migration?
I provide Windows Server upgrade and migration services for businesses across Pakistan and internationally. Whether you need a full migration plan, hands-on in-place upgrade execution, or post-upgrade troubleshooting — I can help remotely, on your schedule.
Services Offered
- Windows Server 2025 upgrade planning and execution
- Active Directory migration and schema upgrades
- Hyper-V host upgrades and VM migration
- Windows Server troubleshooting and recovery
- Azure hybrid server management
Email: itexpert@navedalam.com
WhatsApp: +92 311 935 8005
Website: navedalam.com
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About the Author
Naveed Alam is a certified Network and Cloud Engineer specialising in Windows Server infrastructure, Active Directory, Hyper-V, and Azure hybrid environments. With 50+ completed projects across Pakistan and internationally, Naveed helps organisations plan and execute server infrastructure upgrades safely and efficiently.
Certifications: Cisco CCNA · Microsoft Azure Fundamentals (AZ-900) · CompTIA A+ · Fortinet NSE 4
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