[horde] IMP not shows messages

[Marco Modesti]

Hi, I'm using Horde Webmail Groupware 1.2.9 and I've a strange behavior on one of my user.

This user has 12 messages in Maildir, but after logging in webmail, horde shows nothings (but there is the message "12 mail in INBOX").
I tried to delete every entry on horde_prefs table for this user, but without solve my problem.
By the way, I can view successfully see the messages logging via IMAP (for example with Mozilla Thundebird).
Any suggestion?
Thankyou