Stormonts, Does user A and user B have separate logins when using mail? Could it be that the users have different mailbox archiving policies configured? Austen
Unfortunately, the PST migration task scans the network based on file extension for PST files. One workaround I suggest is to use a utility called "renamer" to rename the extension of these "Non Outlook PST files". Then run the PST Migration utility ...
Do you get the same error when you perform a manual archive of email? If this works, then that tells me there is a configuration error with your provisioning group setup.