Configuring SquirrelMail 1.4.5 or older
Since 1.4.6 and 1.5.1, SquirrelMail contains pre-defined settings for use with the Dovecot IMAP server's default maildir configuration. Here are the instructions on how to configure those settings in SquirrelMail 1.4.5 or older:
1. Apply the Dovecot IMAP preset
conf.pl > D. Set pre-defined settings for specific IMAP servers > dovecot
2. Change the default folder prefix to an empty string.
conf.pl > 3. Folder settings > 1. Default folder prefix
3. Change the IMAP server type to "dovecot".
conf.pl > 2. Server settings > A. Update IMAP settings > 8. Server software > dovecot
Don't set the IMAP server's type to any other server unrelated to Dovecot since SquirrelMail might apply work-arounds for server specific bugs in the selected IMAP server - bugs that doesn't apply to Dovecot.
The settings were tested on Dovecot 0.99.14 and 1.0alpha with default namespace settings. If a more recent version of Dovecot is used, or if you're using custom namespace settings, these settings might not match your layout.