[Dovecot] PDF corruption issue

[Michael Dunne]

Greetings,

I have several users reporting that PDF attachments are coming in  
corrupted. They are using either thunderbird or outlook on windows xp.  
I have flushed the cache files for the users, but the problem still  
persists. Could anyone offer some troubleshooting tips?

Thanks in advance for any assistance.

Below is my version and config.

Regards,

Mike

dovecot --version
1.1.7

dovecot -n
# 1.1.7: /etc/dovecot.conf
Warning: fd limit 1024 is lower than what Dovecot can use under full  
load (more than 1792). Either grow the limit or change  
login_max_processes_count and max_mail_processes settings
# OS: Linux 2.6.18-92.1.13.el5 x86_64 Red Hat Enterprise Linux Server  
release 5.2 (Tikanga)
base_dir: /var/run/dovecot/
log_path: /var/log/dovecot
listen: [*]
ssl_key_file: /etc/pki/dovecot/certs/dovecot.pem
login_dir: /var/run/dovecot/login
login_executable(default): /usr/libexec/dovecot/imap-login
login_executable(imap): /usr/libexec/dovecot/imap-login
login_executable(pop3): /usr/libexec/dovecot/pop3-login
login_max_processes_count: 384
login_max_connections: 384
max_mail_processes: 1024
verbose_proctitle: yes
first_valid_uid: 10
mail_privileged_group: mail
mail_location: mbox:%h/mail:INBOX=/var/spool/mail/%u
mail_debug: yes
mail_full_filesystem_access: yes
mmap_disable: yes
mail_nfs_index: yes
lock_method: dotlock
mbox_read_locks: dotlock
mbox_write_locks: dotlock
mail_executable(default): /usr/libexec/dovecot/imap
mail_executable(imap): /usr/libexec/dovecot/imap
mail_executable(pop3): /usr/libexec/dovecot/pop3
mail_plugin_dir(default): /usr/lib64/dovecot/imap
mail_plugin_dir(imap): /usr/lib64/dovecot/imap
mail_plugin_dir(pop3): /usr/lib64/dovecot/pop3
mail_log_max_lines_per_sec: 25
imap_client_workarounds(default): outlook-idle tb-extra-mailbox-sep
imap_client_workarounds(imap): outlook-idle tb-extra-mailbox-sep
imap_client_workarounds(pop3):
namespace:
   type: private
   separator: /
   inbox: yes
   list: yes
   subscriptions: yes
namespace:
   type: private
   separator: /
   prefix: mail/
   hidden: yes
   subscriptions: yes
namespace:
   type: private
   separator: /
   prefix: ~/mail/
   hidden: yes
   subscriptions: yes
namespace:
   type: private
   separator: /
   prefix: ~%u/mail/
   hidden: yes
   subscriptions: yes
auth default:
   mechanisms: plain login digest-md5
   verbose: yes
   debug: yes
   passdb:
     driver: ldap
     args: /etc/dovecot-ldap.conf
   userdb:
     driver: ldap
     args: /etc/dovecot-ldap.conf
   socket:
     type: listen
     client:
       path: /var/spool/postfix/private/auth
       mode: 432
       user: postfix
       group: postfix