PST files are, in fact, the only way to store Outlook data locally, and Mestha is correct, the file should not be on a network store while Outlook is using it -- one of literally dozens of "gotchas" with Outlook.
I remain as hopeful in 2009 that the NEXT version of Outlook will fix some of the long-standing issues (esp with POP & IMAP accounts) as I was in 2002! Fortunately, I am patient, and for those clients who are not so patient, there are myriad other mail clients out there (I personally switched to Thunderburd when Outlook 2007 kept corrupting my IMAP store!)
In any case, while it is important to note that the PST file must be on a local disk while being accessed, that does NOT mean it cannot be part of a valid roaming profile!
DOH! Another Outlook gotcha -- the DEFAULT location for a PST file is in "Local Settings" -- which means it's not part of the roaming profile. However, you CAN force the file to be located somewhere local that IS part of the local profile. Personally, I relocate PST files from "Local Settings/Application Data" to just plain "Application Data" (which IS part of the roaming profile!). (NOTE: In Vista, I'd move it to the ROAMING folder heirarchy!)
There is a registry setting you can change to force the creation of new folders into your new location, and if you're really swift, you can make the registry change via group policy (or a login batch file).
The fact is though, Outlook remains one of the most popular email programs for the same reason Norton & McAfee remain best sellers in the Anti-Virus market -- a good reputation from "ancient" times (5 or more years ago), in spite of newer products that far outshine it (all of them, in their fields).
Never the less, in today's corporate environment, as an IT professional you can't just go around telling people they "can't use Outlook" (unless you have a KILLER resume and don't mind sending it out again!). So get used to PST problems -- in particular, learn the default locations for the scanpst.exe program for the different versions of Office your support. Oh -- and don't let users keep important data (e-mails) in PST files -- switch IMMEDIATELY to IMAP on your mail server! (Again, personally I disable POP access both by denying the process AND by blocking the ports (just in case an update turns the process on again!))
I hope this helps!
Dan
IT4SOHO
