Windows Server 2016 End of Support: SMB Options & Costs

Windows Server 2016 reaches the end of extended support on January 12, 2027, after which Microsoft no longer provides security updates. For a small or midsize business without dedicated IT staff, rough replacement costs are about 800,000 to 2 million yen for a new server, 100,000 to 500,000 yen for a NAS, and 300,000 to 1 million yen up front plus monthly fees for cloud migration. With about three months left, the realistic approach is to inventory your servers this month and decide on a destination by November.

This article walks through what to check, which options exist, and what they cost for companies that have been running an on-premises Windows Server 2016 as a file server, an Active Directory domain controller, or a host for accounting and sales management packages. We keep jargon to a minimum so that business owners can use it in discussions with staff and vendors. For a broader view of end-of-life planning, see our end-of-life (EOL) preparation guide.

Windows Server has two support phases: mainstream support and extended support. Mainstream support for Windows Server 2016 already ended on January 11, 2022, and the server is now in extended support, which ends on January 12, 2027.

Once extended support ends, newly discovered vulnerabilities are no longer patched. The server does not suddenly stop working; it keeps running as it does today. But known holes stay open for attackers. Ransomware, which encrypts data and demands payment, often spreads precisely through unpatched holes in old servers.

An unsupported OS can also hurt you in other ways: answering customers' security questionnaires, meeting cyber insurance requirements, and passing certification audits can become harder. The real business risk is that you can no longer say "it works, so it's fine."

Before choosing a destination, you need an accurate picture of what you have. Even an office manager doubling as the IT person can sharply improve the quality of quotes by filling in the items below.

- Number and location: how many Windows Server 2016 machines, and whether each is physical or virtual (Hyper-V, etc.)
- Roles: file sharing, domain controller, printer sharing, database, business application host, and so on
- Users and devices: how many people and PCs connect (this directly drives the number of CALs)
- Application compatibility: whether your accounting, sales management, attendance, or CAD software supports the new Windows Server. Ask the vendor
- Data volume: total size of shared folders and how much is actually in active use
- Internet exposure: any function directly reachable from the internet, such as Remote Desktop or VPN
- Hardware age: purchase date, maintenance contract, disk health
- Backups: what is backed up, where, how often, and whether a restore has ever been tested
- Contracts and licenses: OS license type, CALs, expiry of application maintenance contracts
- External connections: site-to-site VPN, integrations with partners' systems, and scan-to-folder destinations on copiers

Two things are easy to miss: software that only runs on this particular server, and copiers whose scan-to-folder destination is a shared folder on the server. Many companies only notice after replacement, when scanned documents stop being saved.

Migration options fall into four broad groups. The best fit depends on company size, the business software you use, and whether you have anyone who manages IT. Costs are rough guides and vary with the number of servers, data volume, and vendor.

There is rarely a single right answer. A combination is common, such as moving file sharing to Microsoft 365 while leaving only the accounting software on a small new server or a cloud VM.

The smallest change is to install Windows Server 2025 on a new server machine and move data and settings over. This is a realistic choice for companies whose business package assumes it runs on an in-house server. For 10-30 users, hardware, the Windows Server 2025 license, CALs (client access licenses), and setup together typically run about 800,000 to 2 million yen.

Two points deserve attention. First, upgrading the OS in place on the old server is hard to recommend: hardware bought around the time Windows Server 2016 launched is likely 8 or more years old, and disk and power-supply failure risks are rising. A new OS on failing hardware does not help. Second, you must buy CALs for the new version; CALs for the older version will not let clients connect to the new server. You need as many as your users or devices require.

The key cost questions are how many years you will use it and how you will maintain it. Physical servers need replacing again in 5-7 years, so the annual cost can end up close to the cloud. If your server is mostly a file server, our NAS vs. file server cost comparison may also help.

If the server mainly does file sharing, replacing it with a NAS is the cheapest route, at roughly 100,000 to 500,000 yen depending on capacity and redundancy (protecting data across two or more disks). Note that a NAS does not replace a Windows domain (Active Directory). Companies that need fine-grained per-user access control should plan the design carefully.

Going a step further, you can move file sharing to Microsoft 365 SharePoint and OneDrive (or Google Drive) and user management to Microsoft Entra ID (formerly Azure AD, cloud-based user management). Then you no longer need a server on site. A typical guide is 200,000-800,000 yen for initial migration work, 300,000-1,000,000 yen for AD to Entra ID migration, and licensing from about 2,000 yen per user per month. The benefits are access from home or on the road, no server maintenance, and built-in backup and version history. Details on process and cost are in our Microsoft 365 migration cost guide.

The downsides are the ongoing monthly cost, the need to rethink folder structures, and the possibility that older applications that expect a network drive will not work. If your accounting software saves data to a fixed shared folder on the server, that part needs separate handling.

If your business software only runs on a particular Windows Server, you can run the server itself as a virtual machine (VM) in the cloud. You no longer keep hardware on site, and hardware failure risk drops. A rough guide is 300,000-1,000,000 yen for migration and 20,000-100,000 yen per month.

Azure sometimes offers Extended Security Updates (ESU) for older Windows Server versions when they run on Azure. For Windows Server 2016, Microsoft may offer paid ESU, but availability, terms, and pricing can change, so please confirm the current situation with Microsoft or a reseller. ESU only buys time; eventually you still need to move to a supported OS.

Cautions: the monthly cost continues for as long as you use it, you must design how office PCs connect (VPN, etc.), and slow connections can make business software sluggish. It is wise to test on a small scale first.

Even if migration will not be complete by January 2027, reducing risk is better than doing nothing. All of the following are bridges to migration, not permanent fixes.

- Stop direct internet access: close published Remote Desktop and router port forwarding first
- Segment the network: place the old server in a network separated from regular PCs and the internet (VLAN, etc.)
- Turn off what you do not use: disable unused services, shares, and accounts
- Strengthen backups: keep regular copies somewhere isolated from the network (external disk, another site, cloud) and confirm you can restore
- Review administrator accounts: stop reusing passwords and remove unnecessary admin rights
- Confirm maintenance and contacts: know who to call and when if the hardware fails

Even with these in place, the fact remains that newly found vulnerabilities will not be fixed. Keep looking for ways to pull the migration date forward.

Today (October 5, 2026), about three months remain. Hardware can take several weeks to arrive, so the sooner you decide, the better. A suggested schedule:

Vendors are less available around the New Year. Finishing the cutover in December and using January as a buffer is the safest plan. If you have integrations with partners or inventory systems, start even earlier.

- Postponing the compatibility check: the software does not run on the new OS and you face a replacement or large extra costs
- Miscounting CALs: confusing user and device counts leads to shortages or over-buying
- Quotes that omit data migration and setup: comparing only hardware prices leads to surprise extra charges
- Starting without a backup: a problem during migration loses data
- Forgetting scan-to-folder, printer, and shared-folder connections: staff flood the help desk after cutover
- Forgetting to wipe data when disposing of the old server: a cause of information leaks
- Putting it off because it still works: panic after a ransomware incident

Most failures come not from technical difficulty but from missed checks and running out of time. For general thinking about end-of-support preparation, see also the EOL preparation guide.