Network setup

This is similar to a problem I posted a short time ago. I downloaded the new Win 10 anniversary update and it wiped out all my network connections. I have one Win 10 machine and one XP Pro machine the happily talked to each other until the latest win update. On my Win 10 machine, I can both see and talk to the XP machine. From the XP machine, I can see both computers, but can open anything on the Win 10 machine. I get a message that says I don't have permission and to see the administrator. I am the administrator. This is the same type problem I had with the last windows update, but the problem disappeared, now it's back.
Can someone tell me how to get permission to open these files.