Follow these steps to remove/reset the default map password:
1) Shutdown NTM.
2) On machine where is NTM installed find 'Credential Manager' (Control Panel\User Accounts\Credential Manager)
3) In Credential Manager find the 'default' NTM credential (username = NTMuser ) and remove it.
4) Start NTM.
5) here press 'New Network Scan' button and enter new password encryption
Note: Existing maps will continue to use the password with which they were created.