Even if a Public Folder is explicitly nominated to be archived within an archiving policy run, the content of the folder is not actually processed (content archived and the original message replaced with a link/stub).
This could be due to either:
*The content of the public folder had previously been archived and then 'un-archived' and where the re-archiving threshold value had not been exceeded.
*The nominated Public Folder is Replicating, a Replica, Public Folder Referral or an Affinity Folder. These folders are not processed to ensure data replication and email network traffic does not exceed normal parameters.
*For the former reason above, the user could simply wait until the re-archiving threshold time had been exceeded and try again or the user could reduce the re-archiving threshold time.
*For the latter reason, the user could make sure the Public Folder is not one of the types not processed.