[Dovecot] Can't create subfolders of my INBOX or delete folders with IMAP

[Matthew Exon]

Magnus Holmgren wrote:

> Well, the solution could be using Maildir instead of mbox as mail
> storage format. Since the traditional mbox format uses one file per mail
>  folder, and one directory per subfolder, you can't keep both mail and
> folders in the same folder. (A folder is either a file containing mail
> or a directory containing other files and directories, but not both).

OK, that was something I was considering - I just didn't know if it 
really would solve the problem.  It raises a bunch of questions though:

1) Is there some system wide setting for this?  I don't want to port my 
own mailboxes, and then have it be the same old mbox stuff for the next 
person I create an account for.  A lot of the documentation sorta 
answers this, but it assumes you're setting up a brand new system, not 
trying to modify an existing one.

2) What's the best way to do this on a Debian system?  Was there some 
setting I missed when I was setting up the box?  I would much rather set 
a debconf setting than fool around inside a config file.

2) What's going to happen to /var/spool/mail?  That looks like a mbox 
thing.  I'd much rather have all my mail in one place, rather than in 
two places like now.

I installed mb2md, but then I got cold feet about whether it was likely 
to work or not, so I haven't run it yet...

Thanks for your help,
Mat