You can delete an archive, provided that the Administration Console shows a status of Available or Closed.
Note the following:
There is no undo when you delete an archive, and you cannot stop the deletion process.
Be careful about deleting an archive that still has an associated mailbox. There will be many errors from the Exchange Mailbox task when it tries to archive to a deleted archive. Make a note of those users who have access to the archive and then get them to change their archiving settings, so that they do not try to archive to the archive you are about to delete. Use the Permissions tab on the archive's property page to find out who has access to the archive.
To delete an archive
In the Administration Console, with the archive displayed in the listing, press F5 to refresh the view. This shows you the archive's current status.
Right-click the archive that you want to delete and, on the shortcut menu, click Delete.
When prompted, confirm that you do want to delete the archive.
The archive's status changes to Marked for deletion. You can no longer view the properties of the archive and shortcuts to items within the archive no longer work.