Had an issue with Windows 10 file sharing in my home network the other day. The issue was that when I was to connect one of my Windows machines to the Homegroup, all of them were saying “USER on PC has created a homegroup on the network”, where USER and PC listed on one machine was the one of the other on the network. That was fine, until I were to connect and was promped to enter a password – WHAT PASSWORD?
The reason was aparently that when multiple machines had created a Homegroup for file and printer sharing, none of them showed the Homegroup password to be used.
The solution was apparently (after fidling with it for a while) to turn all machines off, start one of them over again and finally I could establish a Homegroup and got the password required for the other machines to use.
Here is Microsofts response to the issue.