Greetings. The latest version of Windows 10, 20H2, downloaded into two of my computers. They could no longer be accessed on the local network, and they could not access one another for file sharing. A third computer sensed them but could not access them. I turned off Avast for 1 hour on one computer. It became visible on the network again, but not fully accessible. I did not write down the exact sequence of events but I think it remained visible after turning on Avast again, or resetting.
The network options under Windows Security, Firewall & network protection are not available when Avast is turned on. They are grayed out. When you turn off Avast, Windows Firewall automatically turns on and they become visible.
To fully recover network access, I had to go to Control Panel, Manage advanced sharing settings, and I turned on sharing, and under "All Networks" I turned off Password protected sharing. I assume the Windows 10 update changed those options.
