Ken, sole proprietor / instrumentation and equipment engineer and technologist

Topic: NAS connected to Ethernet-wired LAN and mobile workstations that are regularly disconnected and reconnected

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I have a LAN with seven machines (five are mobile workstations) and two printers and several other networked appliances, including a NAS (network attached file server).  My NAS is a Linux device, as opposed to a Windows-OS file server.

What I have found is the following:

1. If any form of Windows Network Discovery (WNDy, private and/or public) is enabled one will, or at least may, find that WNDy generates requests to the LAN router that will disable internet access on ALL machines (via spurious WIndows-generated overload of the router) on the LAN if the NAS is “mapped” or mounted at the time of physical disconnect from the LAN. This is a new “feature” or dysfunction of  Windows (in my case, Win10 Pro). MS seems to acknowledge that this malfunction has been created (by them, without any notification that I could find) in recent years.
2. Hence, I recommend to any user of Windows such as myself and my business(es) that if one or more NASs are used, and they are mounted to mobile workstations that are used as MOBILE workstations, all WNDy should be disabled.
3. I suppose that even for a stationary workstation, if the Ethernet cable were to be  disconnected for any reason,  such as repair and maintenance, the same would apply.
4. Additionally, it seems a prudent precaution to try to remember to unmount or disconnect any mapped network data-storage drives that are not Windows Server-OS machines on a mobile machine prior to detaching from the LAN. 

Before troubleshooting the problem, I found that I had to power-cycle the router to reestablish internet access on the LAN. This was a time-consuming, not to mention confusing and startling (at first), downtime event that can be avoided by adhering to the steps outlined above. Possibly there are other approaches that could work as well. But I am reporting what I’ve just been able to troubleshoot and resolve this afternoon for any other users in similar circumstances.

P.S. The irony, and not an uncommon one, for my case was that the OEM guidelines for the NAS installation instructed, or recommended, turning on Network Discovery. And one thing led to another ….  after that. So, even if WNDy is enabled for an initial installation using OEM software, I recommend that it be disabled after the installation is completed.