Issue with private LAN

You need to make sure network discovery is turned on.
https://www.home-network-help.com/network-discovery-in-windows-7.html

Yes, Network Discovery is turned on, and I can ping the missing devices from a command prompt.

OK. The next thing to check is that your services are running correctly.

1. Type Window+R to get a "Run" window
2. Type "services.msc" (without quotes) and press enter
3. Scroll down until you find "Function Discovery Provider Host" and "Function Discovery Resource Publication" services.
4. Make sure they are running. If they are not, start them. You may also wish to change the startup type to "Automatic" if it's not already so.
5. Also make sure "SSDP Discovery" and "UPnP Device Host" are running.

See how that works for you and get back to me.

Thank you.  All four services were already started.  Those which were "Manual" have been changed to "Automatic".

Hmmm...

OK, next question. Does this behave the same whether you're connecting with WiFi or a physical connection?

We have a couple of laptops in our office that don't discover devices over WiFi but have no problem with discovery if connected via an Ethernet cable.

Check whether or not your WiFi connection is private or public. That can make a difference.

It will take some time to test discovery with an ethernet cable.  I will post again afterwards.  Thank you...

The missing devices do not appear with an ethernet connection.  The WiFi is a home network.

OK, let's backtrack a little. Even though network resources are not appearing in the Explorer window, you can still access them via a typed UNC path, correct?

Do other devices on the network show this laptop as a device?

Have you tried disabling the Norton Firewall feature (temporarily, of course) to determine if there's something there that's blocking access? One way I can think of to ensure this is a non-issue would be to reboot the laptop using Safe Mode with Networking. That way, Windows will launch with the absolute minimum resources required to run network services.

The devices can sometimes be pinged, and sometimes they cannot.  Disabling the Norton Firewall did not change the behavior.  I will try Safe Mode with Networking...

In Safe Mode with Networking, the LAN Explorer window could not be accessed ("You do not have permission to access...") and no device could be pinged.

Ugh... This is vexing. I'm running out of ideas. Let me ponder it a while and see if I can think of anything else. Also, maybe someone else can chime in with an idea or two that I didn't think of.

I appreciate your thorough and systematic approach.  Since devices sometimes can be pinged, and sometimes cannot, I'm wondering if the WiFi adapter may have developed a hardware issue.

That's possible but seems unlikely. It seems even more unlikely since we eliminated the WiFi adapter earlier by trying a wired connection.

I'm still thinking this is a software issue. I found a website that suggests a few additional steps that I don't think I considered above. See if any of this gets you up and running.

https://www.iseepassword.com/blog/devices-not-showing-up-under-network-in-explorer/

Thank you.  Please allow me some time to research and test.  My next post may be in a day or so. I will also try that notebook with another operating system which is installed.

Nice job Russ!

By the way, I have seen this issue on other networks. One solution was to change the workgroup name  to anything other than Windows Default. Make up your own name.  You will have to change that everywhere, and it’s a pain, but it has fixed this something similar to this problem in the past. Worth a shot if all else fails.

Do put all the computers in any workgroup except the default WORKGROUP., ie name the workgroup something like MYHOUSE. Restart them all (sorry, I said it was a pain) and everything should magically appear.

Thank you both.  I tried all the steps in that article, unfortunately without improvement.  The workgroup has always had a unique name.  This laptop previously detected all devices in the network, and then there was a system crash which required re-installing and reconfguring some devices and applications.  Since then, the LAN issue has developed.  Moreover, I now recognize that the WiFi network needs to be disconnected and reconnected manually, every 10-15 minutes, or there is no internet access.  Maybe it is a hardware issue.

That is sounding like a potential hardware issue. I assume that no other users are having that same WiFi issue?

I don't know what else to suggest other than a a full system wipe and starting over. The crash may have killed something in a file or preferences file that is showing up as this problem.  Sadly, no assurance a clean install will make any difference and it is a lot of work. But if you think the computer is gone anyway, it might be worth a try.

I'm afraid I'm with Owen here. I've really run out of things to try other than a full system wipe. It still might be a hardware issue but I kind of doubt it.

Thank you both for all your input.  I think I will try an in-place upgrade/repair before giving up.  If I learn anything, I'll post again.

Today, all devices appear in the LAN Explorer window, and connectivity works in both directions.  I did not change anything, so it is mystery to me.  I'm making a disk image, to preserve all settings and conditions which are applicable at the moment.  Thanks again for your interest and guidance.

How odd. Thanks for letting us know. What had you done just before it started working?

I didn't make any intentional changes.  We had a power interruption, so the system was re-started.  But I re-started the system countless times, before today, and it didn't make any difference.

Well, if the problem comes back. you can always come back to EE!  :-) Thanks.

Thank you.  I did have an afterthought about the power interruption which preceded the resolution of the issue...  That caused the WiFi router to reboot.  It's conceivable that there was some blockage in that router, which was rectified by restarting it.

DOH! That should have been my very first suggestion...

"Have you tried turning it off and on again?" :)

No.  We run a B&B, and guests are frequently logged on to our WiFi guest network.  I'd prefer not to interrupt their connection unless it is unavoidable.