Many EV customers are doing PST migrations, and this is something that you should be aware of, I think.
EV will scan machines for anything with a PST extension. It doesn't really know at this point whether a file that it finds is truly a PST or not. There are two issues here :-
* EV finds a file that has a PST extension, and it's not a PST.. opening it with MAPI will then cause all sorts of issues!
* EV finds a file that is in fact a PST.... but it's a Sharepoint PST.
With Sharepoint 2007 you can synch document libraries to a "client", ie Outlook. When you do that a PST is created on the client machine which contains hooks back up to the Sharepoint document library and things are kept in synch by Outlook. It's really good, and it's really bad.. for PST migrations.
The first issue above has been fixed in Enterprise Vault already (8 SP 2)
The second issue is to be fixed shortly....