[Dovecot] Older messages not showing up after reinstall

[dclist]

I reinstalled Ubuntu, keeping my maildir directories. Messages older than
the date of reinstall are not being served by dovecot. The messages show up
normally in my MUA if I load the maildir directory directly.

I assume there is a file somewhere where dovecot is keeping a list of seen
messages which I need to reset. The old messages appear to be in
dovecot-uidlist. I tried moving dovecot.index* to no effect.

How do I get the pre-reinstall messages to be served by dovecot?

# 2.1.7: /etc/dovecot/dovecot.conf
# OS: Linux 3.8.0-31-generic x86_64 Ubuntu 13.04
auth_debug = yes
auth_debug_passwords = yes
log_timestamp = "%Y-%m-%d %H:%M:%S "
mail_debug = yes
mail_location = mbox:~/mail:INBOX=/var/mail/%u
mail_privileged_group = mail
namespace inbox {
  inbox = yes
  location =
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix =
}
passdb {
  args = /etc/dovecot/password
  driver = passwd-file
}
passdb {
  driver = pam
}
plugin {
  fts = squat
  fts_squat = partial=4 full=4
}
protocols = imap
service auth {
  user = root
}
ssl_cert = </etc/dovecot/dovecot.pem
ssl_key = </etc/dovecot/private/dovecot.pem
userdb {
  args = uid=vmail gid=vmail home=/home/vmail/%u
  driver = static
}
userdb {
  driver = passwd
}
protocol imap {
  mail_plugins = fts fts_squat
}
protocol pop3 {
  pop3_uidl_format = %08Xu%08Xv
}