I upgraded a workstation to Win 10 Pro. The system, System X, has two admin users, A and B. A is logged on to System X. Volume C is shared from the root on System X, All admins on the system have permissions to Share C with full control. B is logged on to another system, System Y (Win 8.1). B can access (read) almost all folders on System X from System Y, but cannot write to the folders as he did in the past. I attached a screenshot of the sharing options, which are the same for all networks. Thanks.