Ignore Exchange "Public Folders" ?

I have the same problem.

Apple Care (and their IMAP "team" ) informed me that that there was nothing that could be done on from our end. The system admin of the exchange server has to set your account such that you don't see these folders. We'll see...

One can turn off the spotlight indexing using Preferences > SpotLight > Privacy, but that change still doesn't get you out of Mail.app synchronizing the Public Folders to your drive (or making you click on a dialog whenever it can't read the "public" folder!) --- I second the request for folder subscriptions in Mail.app. Its important.

Every other modern mail client has a Subscribe/Unscribe feature for shared folders. Mail.app doesn't, and it's a serious limitation. My mail server stores lots of mail, and Mail.app is unusable for me for just that reason. I'm stuck using Thunderbird, which is really sad. I LOVE Mail.app, but I can't use it! Even if there was some Terminal.app workaround I'd be happy!

Well, this is one of the main reasons Mail isn't really a full-featured email client. The simple fact is you can't unsubscibe folders using Mail. There is no provision for that functionality. I can't think of any other client so limited.

I use IMAP with all folders at the root of the message tree. Not unusual that. Mail will therefore show the hidden .mailboxlist and cache folders. It's not even clever enough to automatically unsubscribe these folders which are obviuosly meant to be hidden.

That's not all either. Mail doesn't allow you to select which special folders you want to use for Sent, Drafts, Trash etc. This means my sent mail can't be synced on the server.

I had high hopes for the Tiger release, but nothing's changed. It's just been badly re-skinned. Mail has several steps further to go before it becomes a real mail client. It's currently rubbish.

Exchange 2000 server and Mail, saw the same issue here. Have you tried configuring as an Exchange-type configuration?

That resolved the public folder r/w access error dialog issue for us.

As far as Spotlight, dropping ~/Library/Mail folder should disable indexing on any cached Mail files.

That's not all either. Mail doesn't allow you to
select which special folders you want to use for Sent,
Drafts, Trash etc. This means my sent mail can't be
synced on the server.

You can't select a server stored mailbox and at the menu bar, go to Mailbox > Use This Mailbox For and select Sent, Drafts, Trash?

I know of (at least) three ways to address this problem:

ℹ A tip on macOSXHints describes one way to fix this if you have access to the Windows Active Directory settings.
(ii) Comments on that tip describe several other workarounds.
(iii) Lars Eggert has written a Perl script that will also filter the folders.