update: I discovered the reason I was getting subfolders in imap was that I had mistakenly named the imap server director IMAP/ instead of INBOX/ - after restoring this setting and trying Shredder again, it did manage to show the contents of folders other than the Inbox without the Alert that I saw before.
update: I discovered the reason I was getting subfolders in imap was that I had mistakenly named the imap server director IMAP/ instead of INBOX/ - after restoring this setting and trying Shredder again, it did manage to show the contents of folders other than the Inbox without the Alert that I saw before.