Inconsistent results from Windows Networking

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Thank you for following up and for mentioning that some of the desktop computers use local accounts without passwords.

Windows includes a security setting called Accounts: Limit local account use of blank passwords to console logon only. By default, this policy is enabled. When enabled, a local Windows account that does not have a password can sign in locally at the computer, but the blank-password account cannot be used to authenticate to that computer over the network. This is a recommendation protecting local accounts used with the Classic network-sharing model with passwords.

For that reason, I would not recommend disabling this security policy or enabling anonymous/insecure access as a workaround. Instead, I suggest testing one affected computer first so that we can determine whether authentication is contributing to the problem without changing the security configuration of the entire network.

For example, using Mars:

1. Assign a password to the local Windows account on Mars.
2. Restart Mars.
3. Make sure Network discovery and File and printer sharing remain enabled for the Private network.
4. From Uranus, open File Explorer and enter \\MARS directly in the address bar.
5. If Windows requests credentials, enter the local username and the new password configured on Mars.
6. Verify whether the shared resources on Mars can now be accessed.
7. Finally, refresh File Explorer > Network and compare the devices shown there again.

This test is important because network access and network discovery are two different parts of the behavior. The fact that the MyCloud NAS continues to work through the mapped Y: drive even when MyCloud is absent from the Network view already demonstrates that a device can remain directly reachable while not being displayed consistently by File Explorer's discovery view. Therefore, adding a password may resolve an authentication problem, but I would not want to promise that it will necessarily make every computer appear consistently under Network.

If \\MARS begins working correctly after adding the password but the computers are still missing from File Explorer > Network, that would be useful evidence that the remaining issue is specifically related to network discovery rather than authentication. Conversely, if the behavior remains completely unchanged, that result is useful as well because it allows the blank-password factor to be separated from the discovery problem.

Moreover, I want to set a realistic expectation about how far this can be investigated through Microsoft Q&A. Microsoft Q&A is a community-based support forum, rather than an interactive diagnostic or remote-support service. From the forum, I can provide troubleshooting based on Microsoft documentation and help interpret the results that you post, but I cannot directly inspect the PCs, router, NAS, Windows event traces, SMB negotiations, firewall traffic, or the effective security configuration across each computer.

Because your environment includes multiple Windows versions, a NAS device, Ethernet and Wi-Fi connections, determining why individual systems are receiving different discovery results may eventually require examination of the actual network traffic and configuration. If the test above does not isolate the problem and you would like the issue investigated beyond what can reasonably be established through forum posts, I recommend contacting Microsoft Support for the currently supported Windows systems. If investigation points specifically to NAS discovery, the NAS manufacturer's support team may also need to examine the device's discovery/SMB configuration.

One additional consideration is Windows 7. Windows 7 reached end of support on January 14, 2020, so I would avoid changing current Windows 10 or Windows 11 security settings simply to maintain compatibility with that computer.

References:

Accounts Limit local account use of blank passwords - Windows 10 | Microsoft Learn

File sharing over a network in Windows | Microsoft Support

LocalPoliciesSecurityOptions Policy CSP | Microsoft Learn

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