Due to a change in company policy, all existing Public Folders (PF) have to be phased out in favour of shared mailboxes. Unfortunately, they don't seem to have any procedures or guidelines for this migration and I can't find much online either.

I've already migrated one of our public folders so far as a sort of test case. Because we still use Exchange 2003, we can't create real shared mailboxes as we would in 2007 or 2010 (With New-Mailbox -Shared ... in the Exchange Shell). Instead, I simply created a new account on the AD and assigned it a mailbox. I then set the PF's permissions to read-only to keep it in a consistent state and copied the entire folder to a local PST in Outlook 2010, from which the folder was in turn copied to the new mailbox. Permissions and Folder Visible were set for all users and the migration was successful.

While this works, the whole procedure feels very hackish to me and not at all efficient. I'd welcome some input on automating or at least streamlining the process.

Additionally, we are unsure of what to do with our mail-enabled Public Folders. Several of these are nested under other PFs, some of which are also mail-enabled. Preserving folder structure is a key requirement and this seems impossible at first glance. I've considered creating dummy accounts for all the email addresses from our mail-enabled PFs and then setting up automated rules to forward messages to a subfolder of the new shared mailboxes, but I am not familiar enough with Exchange to know if this is even possible.

Further points of concern are the Calendars and Contact lists in our public folders. I suppose I'll be forced to create new mailboxes for every one of these we have as well, then set up share permissions for their Calendar and Contact items, but would be happy to be proven wrong.