[Dovecot] Couldn't init INBOX: Can't sync mailbox: Messages keep getting expunged

[David Jonas]

Upon upgrading from 1.0.2 to 1.1rc4 I see this error for many of our users:

  Getting size of message UID=1 failed
  Couldn't init INBOX: Can't sync mailbox: Messages keep getting expunged

Logging in with IMAP I would see a bunch of messages with no subject or 
time and blank bodies (usine horde/imp).

Removing dovecot.index.log, dovecot.index.log.2, or dovecot-uidlist 
fixes the problem for the account (I chose dovecot.index.log). I imagine 
that forces a rebuild of the indexes. Removing other files in the 
directory didn't seem to make a difference, including dovecot.index or 
some arbitrary non-dovecot file.

Is there a more conventional way around this problem?