User.id file for Lotus/IBM Notes
In order to open a IBM (formerly Lotus) Notes .nsf file it may be necessary to have a user.id. This file contains the user's password, encryption keys, and other recovery information. In version 9 of Notes this file is located in a user's App Data folder. You can find its location by going to File . . . Security . . . User Security:
Notes can be configured so that having a password is not enough to open an email database, additional encryption information in the user.id file is requited as well. Even if the user.id is not required for an entire .nsf database it may be needed to open specific messages. When collecting .nsf archives be sure to request the user.id file.