Introduction
Although SMBv1 has long been deprecated due to security concerns, many organizations still maintain legacy servers that only support this protocol. When migrating data from older systems to modern platforms such as Windows Server 2022 or Windows Server 2025, administrators may encounter connectivity issues because SMB1 is disabled by default.
This article demonstrates a simple method to temporarily enable SMB1 on a modern server, transfer the required files, and then disable the protocol again to minimize security exposure.
Warning: SMB1 is considered insecure and should only be enabled temporarily for migration or recovery scenarios. Always disable it immediately after completing the file transfer.
Scenario
In this example:
- Legacy server: Only supports SMB1
- Modern server: Windows Server 2022 / Windows Server 2025
- Objective: Copy files from the legacy server to the new server
Step 1: Enable SMB1 on the Modern Server
Open PowerShell with administrative privileges and run:
Enable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol
Depending on the server configuration, a reboot may be required before the feature becomes available.
Step 2: Connect to the Legacy Server
From the legacy server, map the share located on the modern server:
net use drive-name: \\server\folder /user:domain\username password
Example:
net use Z: \\legacyserver\temp /user:mydomain\sysadminnotes *********
After the drive is mapped successfully, copy the required files using Windows Explorer, Robocopy, or another preferred tool.
Step 3: Disable SMB1 After the Migration
Once the transfer is complete, remove the temporary compatibility feature from the modern server:
Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol
If prompted, restart the server to ensure the protocol is fully disabled.
Why You Should Disable SMB1 Immediately
SMB1 lacks many of the security improvements introduced in newer versions of the protocol, including:
- Enhanced authentication mechanisms
- Improved encryption capabilities
- Better protection against lateral movement attacks
- Increased resilience against ransomware and network-based threats
Leaving SMB1 enabled permanently unnecessarily increases the attack surface of the server.
Best Practice
When dealing with legacy systems, consider SMB1 as a temporary migration tool rather than a permanent solution. Whenever possible:
- Upgrade or replace legacy servers
- Use SMB2 or SMB3 for file transfers
- Remove SMB1 immediately after the migration
Conclusion
When migrating files from older servers to Windows Server 2022 or Windows Server 2025, temporary SMB1 activation may be the only practical option. By enabling it only for the duration of the migration and disabling it immediately afterward, administrators can successfully transfer data while minimizing security risks.