[Dovecot] Dovecot corrupted index cache

[Michael D. Godfrey]

System: Linux  2.6.25.6-55.fc9.x86_64 #1 SMP Tue Jun 10 16:05:21 EDT 
2008 x86_64 x86_64 x86_64 GNU/Linux
Dovecot: dovecot-1.0.14-8.fc9.x86_64

We have used Dovecot for several years.  The error message below appears 
in the system log
quite frequently. I have run a test which shows that this message is due 
to 2 or more users accessing
the same mail (i.e connecting using the same userid).  This happens for 
various reasons including
the fact that some users have their client machine set up (typically 
using Thunderbird) with more
than one account within a single Thunderbird configuration.  Thus, more 
than one person may be
reading or sending mail from a single Dovecot account.

The Dovecot error is:

Dovecot disconnects:
    Inactivity: 13 Time(s)
    Logged out: 2 Time(s)
    in IDLE: 12 Time(s)
 
 **Unmatched Entries**
    dovecot: IMAP(godfrey): Connection closed: 4 Time(s)
    dovecot: IMAP(godfrey): Corrupted index cache file /home/godfrey/Maildir/dovecot.index.cache: invalid record size: 1 Time(s)
    dovecot: IMAP(igodfrey): Connection closed: 4 Time(s)
 ===============
or:
Dovecot disconnects:
    Inactivity: 23 Time(s)
    Logged out: 1 Time(s)
    in IDLE: 6 Time(s)
 
 **Unmatched Entries**
    dovecot: IMAP(godfrey): Connection closed: 8 Time(s)
    dovecot: IMAP(godfrey): Corrupted index cache file /home/godfrey/Maildir/.Sent/dovecot.index.cache: invalid record size: 1 Time(s)
    dovecot: IMAP(godfrey): Corrupted index cache file /home/godfrey/Maildir/dovecot.index.cache: invalid record size: 1 Time(s)
    dovecot: IMAP(igodfrey): Connection closed: 6 Time(s)
 
 ---------------------- Dovecot End ------------------------- 

=========================================================
These errors do not seem to cause any serious problem, but it would be 
good if the problem could be fixed.

I have seen other "corrupted" error reports in the mail archive, but 
they did not seem to be
exactly like this one.