we have unity 3.x in unified messaging mode with 120 subscribers.
Considering that this is a problematic server we decide to install brand new unity 4.05 server and import the subscribers to this server to create new voicemailboxes on it.
Unfortunately when I try to import the subscribers on the new unity I can't see the users that are already assigned as subscriber in the old unity server....
Unity is not seeing the users available for import because the Unity schema specific attributes are enabled by the users being subscribers on the 3.X system. You will need to remove the users from the 3.x Unity and then import into the 4.0(5) system. I don't believe you can digital network a 3.X Unity server to a 4.x server, which would have allowed you to move the users between servers. However, I'll bet there is a way to export user information from your 3.x system into a csv file that you could use to bulk import into the 4.0(5) system.