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

[Matthew Exon]

Yes: interesting effect.  When you create a folder with a trailing 
slash, the created folder is greyed out.  You can then create subfolders 
in the greyed out folders by right clicking on them.  I'd be interested 
to see where this functionality is documented :-/

So your explanation seems right, that I can't delete folders because the 
Trash folder can't have subfolders.  It looks like Thunderbird does have 
some explicit support for the node/leaf model (the greyed out folder 
names), but this support is incomplete, because it doesn't recognise 
that this will make it impossible to delete a folder.

I guess using some other client to delete folders is a solution for that 
- but what I really want to do is to enable INBOX and Trash to have 
subfolders, which must be a server-side thing.  Anyone have a suggestion 
for that?

Josh Burley wrote:
> I had the same problem. When creating a new folder that should contain 
> subfolders, I appended a trailing /. This would enable the folder to 
> contain subfolders. And only leaf nodes could contain messages.
> 
> Along that same line, Thunderbird was trying to put folders into the 
> Trash folder upon deletion. Which wasn't allowed (as far as I can tell) 
> because the Trash folder was a leaf node, and could only contain messages.
> 
> If I tried to delete a folder in Outlook, or a webmail client, it 
> deleted it correctly.
> 
> .josh
> 
> Matthew Exon wrote:
> 
>> Hi,
>>
>> I've been using the dovecot IMAP server for about a year now, and 
>> basically it works.  But there's an annoying problem, that I can't 
>> make any subfolders.  I can only make folders that are at the same 
>> level as my INBOX folder.  Worse, I can't delete folders once I've 
>> created them.
>>
>> I'm using Debian unstable on both the server machine and my client 
>> machine.  The dovecot version is 0.99.13.  For my mail client, I'm 
>> using Mozilla Thunderbird version 1.0.
>>
>> I've done a bit of investigation on my filesystem, and by googling for 
>> all kinds of stuff, but I'm really drawing a blank on this particular 
>> problem.  Most of the general linux email documentation I've found 
>> either doesn't mention IMAP, or doesn't mention dovecot, or both.  I 
>> can barely find any references to the concept of "subfolder" at all.  
>> I really don't want to know anything about email servers, I just want 
>> the bloody thing to work.  Trying to figure out what the hell's going 
>> on is really frustrating!
>>
>> On the server, I seem to have various mailboxes distributed around the 
>> place.  I've got a mail box in /var/spool/mail.  I've got a file 
>> ~/mbox, which seems to be very old and is therefore probably a red 
>> herring. I've also got a directory ~/Mail with a bunch of files in, 
>> one for each of my folders.  Having some of my mail in /var/spool, and 
>> some in my home directory, seems a really horrible way of arranging 
>> things, but anyway...
>>
>> Various online sources seem to suggest that maildir is better than 
>> mbox.  I don't have any particular preference for one or the other, 
>> but I don't want to change if I don't have to because:
>>
>> 1) From experience, I don't screw with settings if I don't have to. 
>> Debian made it that way, and changing it behind Debian's back is a 
>> surefire way to cause trouble later.
>>
>> 2) Any other accounts on that machine (especially ones I might create 
>> in future) will probably still be mbox, causing even worse confusion 
>> later.
>>
>> 3) Porting mailboxes is always risky, and I don't want to lose my 
>> mail, or have incoming email dropped, or accidentally corrupt it, or 
>> anything like that.
>>
>> So I'm not going to do any of that unless I'm sure that it's actually 
>> going to fix the subfolder problem, and until now I haven't found any 
>> information anywhere to guarantee that that's the case.  Intuitively I 
>> can guess that if a folder is just a big file full of concatenated 
>> email, then making a subfolder is going to be pretty much impossible, 
>> but I don't want to guess here.
>>
>> The actual symptoms in thunderbird are:
>>
>> When I select "New folder...", I get the "Create as a subfolder of:" 
>> dropdown hierarchy box thingy, but the "Inbox" option is greyed out 
>> (side complaint: no user interface should ever have a greyed out 
>> option without providing an explanation as to why it's not available, 
>> and what you should do if you want it to be available.  Displaying it 
>> like that is just cruelly teasing the user).
>>
>> When I try to delete a folder, I get a dialog box saying "The current 
>> command did not succeed.  The mail server responded: Mailbox doesn't 
>> exist: <name of folder>".  This is pretty frustrating, because I can 
>> *see* the damn thing in thunderbird.  (another side complaint: "The 
>> current command"?  You're *running* the bloody command, you should 
>> have a better description than that!)
>>
>> For some reason though, I can rename a folder with no problems.
>>
>> I went into /var/log/ on the server, to see what was in the Dovecot 
>> log file about the server errors above, but there *is* no log file, 
>> nor anything in the syslog.  That can't be good.  How do you tell the 
>> sysadmin when there's a problem?
>>
>> Does anyone have any suggestions for how I can fix this?  And if 
>> possible, I want to fix this the Debian way, that is by modifying a 
>> debconf setting or a /etc/default file or something like that, so that 
>> when I upgrade Debian, or uninstall dovecot and then reinstall it, 
>> it'll be handled gracefully.
>>
>> Thanks,
>> Matthew Exon