Windows 11 Pro 25H2 - Network Mapping Issue

This issue is not related to the firewall.

The error indicates an authentication problem rather than a network connectivity issue. In a workgroup environment, Windows must authenticate using local accounts on the target machine, and the correct credential format is essential.

Key points to check:

• Ensure credentials are entered in the correct format: COMPUTERNAME\Username or .\Username
• Remove any saved or cached credentials from Credential Manager on the new Windows 11 devices
• Avoid using only the username, as Windows may incorrectly attempt domain-based authentication
• Verify that the systems are correctly operating in a workgroup context, not attempting domain authentication via cached settings or Windows Hello

In most cases, this issue is resolved by clearing stored credentials and explicitly specifying the local machine account format when mapping the network drive.

Hello Murray, thank you for posting in the Microsoft Q&A community.

Based on your description, the new Windows 11 25H2 laptops are rejecting the Workgroup credentials and throwing a "domain isn't available" error. This is a known behavior on newer Windows 11 devices, especially those using Microsoft Accounts and Windows Hello (PIN sign-in). When you use a PIN, Windows prioritizes modern cloud or domain authentication protocols. When it tries to connect to a traditional local Workgroup share, it attempts to pass a domain token instead of the required local NTLM authentication. Your older laptops likely still work because they were upgraded from Windows 10 and retained their legacy local credential behavior.

To directly answer the questions you asked in the comments regarding the command prompt: The * (asterisk) at the end of the command is required. It tells Windows to securely prompt you for the password on the next line so your password isn't visible on the screen. Do not replace the asterisk with your password.  For the /user: section, you need to input the exact Computer Name of the server, a backslash, and then the username of the account on the server. For example, if your server's computer name is OFFICE-SERVER and the username is Admin, the command would look exactly like this:

net use Z: \\OFFICE-SERVER\Sharename /user:OFFICE-SERVER\Admin *

Because the Windows 11 File Explorer mapping wizard often struggles with Workgroup authentication when a PIN is involved, the most reliable standard solution is to pre-load the credentials directly into the Windows Credential Manager. This bypasses the mapping wizard's authentication entirely. Please try the following steps on one of the new laptops:

1. Open the Start menu, type Credential Manager, and press Enter.
2. Click on Windows Credentials.
3. Click Add a Windows credential.
4. In the Internet or network address box, type the exact computer name of the server (e.g., \\PCSERVER1). You can also try using the server's IP address (e.g., 192.168.1.50) if the name fails.
5. In the User name box, type it in the format of ServerName\UserName (e.g., PCSERVER1\Murray).
6. In the Password box, type the password for that specific user account on the server.
7. Click OK to save.
8. Now, open File Explorer and attempt to Map the Network Drive again. Do not check the box that says "Connect using different credentials"—let Windows automatically pull the credentials you just saved in the Credential Manager.

If that does not work, we can force the system to accept NTLM authentication through the Local Group Policy. Sometimes new Windows 11 25H2 deployments have stricter default security policies that restrict local network mapping. Press the Windows Key + R, type secpol.msc, and press Enter. Navigate to Local Policies > Security Options. Find the policy named Network security: LAN Manager authentication level, double-click it, and set it to Send NTLMv2 response only. Refuse LM & NTLM. Apply the changes and restart the laptop.

To help me isolate the issue further if the above steps do not work, please run the net use command in a Command Prompt and reply with the exact output or System Error code. This will tell us if the failure is at the network level or purely an authentication block.

I will follow up on this thread to ensure your issue is resolved. If the guidance provided helped you navigate to this solution, please consider clicking 'Accept answer'. This officially marks the thread as answered and greatly helps other community members who are searching for a solution to this exact same problem.*

Official Microsoft Documentation References:

• Troubleshoot SMB Mapping: https://learn.microsoft.com/en-us/windows-server/storage/file-server/troubleshoot/troubleshoot-smb-…
• Accessing Credential Manager: https://support.microsoft.com/en-us/windows/accessing-credential-manager-1b5c916a-6a16-889f-8581-fc…

The error indicates that the credentials are being treated as domain credentials instead of local accounts on the two Windows 11 “server” PCs. In a workgroup, the username must be explicitly specified as a local account on the target machine.

Use these steps when mapping from each new laptop to each server PC:

1. In File Explorer, select This PC → Map network drive.
2. Enter the path using the server’s name or IP, for example:
   • \\PCSERVER1\Sharename
3. Check Connect using different credentials and select Finish.
4. When prompted for credentials, enter them in one of these forms so Windows knows they are local accounts on the server, not domain accounts:
   • PCSERVER1\UserName (where PCSERVER1 is the exact computer name of the server and UserName is the local account on that server)
   • or UserName with the More choices → Use a different account option, then PCSERVER1\UserName in the username field.
5. Use the password for that local account on the server PC.

Repeat for each share on each server PC. If the same username/password exists on both the server and the laptop, mapping should succeed without the “domain isn’t available” error once the server name is included in the username.

If mapping still fails, test with net use from a Command Prompt on the new laptops:

net use Z: \\PCSERVER1\Sharename /user:PCSERVER1\UserName *

Enter the local account password when prompted. If this works, the issue is purely how the credentials are entered in the GUI.

Also ensure:

• All machines are in the same workgroup name.
• Network profile is Private, and Network discovery and File and printer sharing are enabled on all PCs.

References:

• Error when you try to access an administrative share on a Windows-based computer from another Windows-based computer that's a member of a workgroup: Logon unsuccessful: Windows is unable to log you on
• Troubleshoot Azure Files connectivity and access issues (SMB)