A platform supports an unmanaged secured workgroup, without a server, for common user access and secure resource sharing among the computers in the group. User accounts are synchronized by replicating and modifying the accounts at each computer of the unmanaged secured workgroup. A computer advertises a change in account information to other computers in an unmanaged secured workgroup. If one of computers in the unmanaged secured workgroup determines that the change is not reflected in the current account information, the computer requests the updated account information from the advertising computer. Any conflicts between user accounts at different computers are resolved before synchronizing the user account in the unmanaged secured workgroup. Also, an application program interface (API) enables an application to query properties of a networked computer system and an unmanaged secured workgroup and to join the unmanaged secured workgroup.