Thanks for a really well written answer. Unfortunately it didn't solve the problem. Learned that the Automatic Removal box should not be checked as if enabled the SMBv1 is removed after 15 days of...

My 4 machine workgroup network, 2 XP and 2 Win 10 machines, was functioning fairly well until the recent "Creator" upgrade. Now the XP machines can no longer see the 10 machines and the 10 machines...