On a new month-old computer with Win10home pre-installed [ Windows 10 Home, Version 1511 (OS Build 10586.71) ], as well as on 9 other machines on the network. (all except for mine are running Win10home, and all were upgraded from Win7 to Win10home using the free Microsoft update method)
Opening File Explorer and clicking on the Network link in the Navigation Pane will show less than half of the computers that are on the network, both in the Navigation Pane under "Network" and in the Content Area under "Computer". The other computers APPEAR to be gone/missing/unavailable.
However, if you click in the Location Bar and MANUALLY type in one of the missing computer names (for example, "\\CHUCK-PC"), then it will now display the shared items in the Content Area, and the newly connected computer name will show over in the Navigation Pane under network. But, when you click the Network link to display the computers again... you do NOT see that newly discovered computer listed in the Content Area... EVEN THOUGH it is still showing over on the left in the Navigation Pane!!!
An additional observation is that if you close the File Explorer, and then re-open it, the manually typed in computer name is now gone from the left in the Navigation Pane... you have to manually type it in again to make it appear.
(note 1: all computers are on the same Homegroup, all are Private Network, all are set to discover and share everything.)
(note 2: attached a Win7ultimate laptop to the system with same Homegroup and it could see and be seen by every single computer on the Network.)
(note 3: the computers which seem to be invisible ARE showing under the Homegroup over in the Navigation Pane, and their Music/Pictures/Videos folders are visible (but not any other shared folders).)
After much trial and error, I finally found a method of trial and success. I tried all solutions offered on various other threads, to no avail. So I tried a few out-of-the box options and found one that seems to be working!!!
We have 10 computers in our office, 8 running Win10 and 2 running Win7, on the same Homegroup. All of the Win7 computers could see ALL of the other computers on the network, no problem. But ALL of the Win10 computers could not see all of the other Win10 computers. How to fix this?
The default in Win10 is to have NETBIOS turned off (or set to auto, which is basically off depending on your router). The trick appears to be turning that NETBIOS setting on. Here are the steps of what I did, on my network, to turn on NETBIOS to get Win10 machines to be able to see each other on the NETWORK tab in File Explorer:
1- Click the Start Menu or Cortana search and type "network." (Or Click on Settings -> Network&Internet)
2- Select Network and Sharing Center when it appears.
3- Click on Change Adapter Settings in the left pane.
4- Right-click on your Ethernet/Wireless adapter and select Properties.
5- Select the TCP/IP v4 protocol and click Properties.
6- Click the Advanced button.
7- Click the WINS tab and check the box Enable NetBIOS over TCP/IP.
8- Click OK.
9- Click OK.
10- Click Close.
I did the above steps on EVERY one of the Win10 computers and then powered it off. After all computers were changed and powered down, I rebooted the main computer that the Homegroup was originally set up on first. Then I rebooted each other computers and voila... I can now see each and every Win10 computer from any other computer.
Hope this helps some of you!