A question was posted recently about networking issues that started with Windows 10. I thought this was nothing since I could see all my computers in my home network, but I started reading and testing, and sure enough, the original Windows NetBIOS networking protocol is broken in Windows 10 1511.
My first test was to open File Explorer, click on Network on the left, change the View to Details, and add the Discovery Method column. All the computers were discovered using WSD, which is a newer networking API from Microsoft. None of the computers were discovered using SMB or NetBIOS.
My next test was to start a command line and run NET VIEW. This command shows all the computers in the network using NetBIOS. Instead of listing all the computers in the network, it instead shows an error 1231 "The network location cannot be reached."
My final test was to try the command "NBTSTAT -r". This should list all the computers resolved by the NETBIOS service. Instead, the listing was just gibberish.
This is insane. This protocol predates Windows and goes back to DOS, and for it to be broken now is incredibly shoddy workmanship by Microsoft and a testament to the foibles of the constant update cycle. Worse, although Microsoft seems to have identified the problem and has a fix (in 11103), that fix isn't even available to the fast ring yet (even though the problem was identified as early as last November), and the ETA for a public release is MARCH.
See the posts by Adam Rudell (ARUDELL) in this thread:
He's a networking guy from Microsoft and he's been very informative.