[Dovecot] Error copying >1 message to virtual mailbox

[Nicholas Riley]

I created a virtual mailbox which maps to a single physical mailbox (in 
Dovecot 1.x I did this with a symlink but had intermittent problems with 
Dovecot 2.0 doing the same.)

However, I can only copy one message at a time into the mailbox.  If I 
try to copy more, I get:

7.16 UID COPY 48531:48532 !/Saved
7.16 NO [CANNOT] Can't save messages to this virtual mailbox

whereas this works fine:

10.16 UID COPY 48531 !/Saved
10.16 OK Copy completed.

The dovecot-virtual file in !/Saved is:

!2011-01
  all

and dovecot.conf:

# 2.0.8 (cde0d403c6ff): /etc/dovecot/dovecot.conf
# OS: Linux 2.6.18.8-linode22 i686 Debian 5.0.7 
mail_location = 
maildir:~/Maildir:LAYOUT=fs:INBOX=~/Maildir/INBOX:CONTROL=~/.dovecot.cont
rol:SUBSCRIPTIONS=.subscriptions
mail_max_userip_connections = 20
namespace {
  inbox = yes
  location = 
  prefix = 
  separator = /
}
namespace {
  location = virtual:~/Maildir/!
  prefix = !/
  separator = /
}
passdb {
  driver = pam
}
plugin {
  antispam_backend = dspam
  antispam_signature = X-DSPAM-Signature
  antispam_spam_pattern_ignorecase = *spam
}
protocols = imap
ssl = required
ssl_cert = </etc/ssl/certs/dovecot.pem
ssl_key = </etc/ssl/private/dovecot.pem
userdb {
  driver = passwd
}
protocol imap {
  mail_plugins = " virtual"
}

Thanks.
-- 
Nicholas Riley <njriley at illinois.edu>