I think a great place to start would be to use this excellent Unity Tool;
Cisco Unity Tools - Subscriber Information Dump (this can create a .csv file that contains much information including the following)
Date of subscriber creation. The date the subscriber was added to the Unity system.
Time of Last Call. Indicates the date and time the user called in to check messages last. This can be handy for finding out which boxes have not been access at all or which ones have not been accessed in a long time. This value is in GMT and not your local time, keep that in mind.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.