Updated December 9, 2016
This article explains why the maps encryption password cannot be reset when the password is forgotten.
All NTM versions
By security design, maps credentials are saved per user. Thus, other users do not have rights to read the map. NTM does not allow map password restoration. All credentials are stored in a Windows user credential vault that you can view from Control Panel > All Control Panel Items > Credential Manager.
To let other users view the map, log in using your Windows account that can open the map and click File > Export > Map and give the map file a new password. This map can now be opened by other users using the specified password.