[Dovecot] inbox doesn't exist, and quota calculation error

[Mike Abbott]

Perhaps related to the other errors I just reported, I also see a few of these in the dovecot-2.0.3 logs:
lda(pid 8212 user user3): Error: Opening INBOX failed: Mailbox doesn't exist: INBOX
lda(pid 8212 user user3): msgid=<201009240906510365.1gj1fpfhrhhm9 at mail>: save failed to INBOX: Mailbox doesn't exist: INBOX
lda(pid 8212 user user3): Error: BUG: Saving failed to unknown storage

and some clients report receiving this IMAP error:
tag NO Mailbox doesn't exist: INBOX

although in general mail delivery and IMAP work, and these users' Maildir++ directories do exist and look OK.  This error did not occur for the user1 or user2 in the other report.


And here's a third kind of error:
imap(pid 5722 user user4): Error: stat(/path/to/mail/user4/tmp/ͼ) failed: No such file or directory
imap(pid 5722 user user4): Error: Internal quota calculation error

That path looks like a memory munge.