After thinking about the problem this morning I thought perhaps the best way to handle this would be to delete the account, thus clearing out the faulty folders and then reestablish the account which would get a fresh sync with the folder structure on the server.

What do you think about this possible solution?

Well no responses yet, but I have been doing more digging and it appears that TB has limits on how deep a file hierarchy can go because of system limits to the number of characters that can be used for the folder path names. Here is what MozillaZine says about TB folder hierarchy limits:

"The depth of the folder hierarchy is limited by the path to last folders header. That can't exceed the operating systems maximum path length (usually at least 255 characters). That is not the same as what you see in the folder pane, its includes the path to the parent folder in the profile (which might be over 100 characters), and five additional characters (back slash plus .sbd) for each child folder. If you run into this limit you can display more folders by moving the profile or the accounts directory closer to the root of the drive, so that less of the total path length is wasted. There is additional overhead if any of the folders have non-ASCII characters. For example, if its a IMAP account the server would send the string as modified UTF-7, which more than doubles the number of characters. "

So it looks like what I need to do is get rid of many of the "children" to shorten up the paths. Probably a good "opportunity" to clean house anyway.

I will report back if this worked.

Problem solved after huge rearranging of my saved folder structure on my Comcast email server to get rid of any child folders deeper than one child. All the folders are now syncing just fine.

Looks like there really is a limit on file tree "depth" due to the above noted limitations (previous post). Would have been nice to know this up front. Sigh....

Hopefully this documentation helps someone else.