[Dovecot] Folders compat. problem ?

[Frank Bonnet]

Hi

A user here has a strange problem when I moved my imap server from
UW-IMAP to Dovecot.

A folder created monthes ago with mozilla mail (windows client) became
suddenly invisible when I stopped UW then started Dovecot.

I really think that IMAP created folders a fully compatibles between
UW and Dovecot but I'm curious to know from where does come this trouble ???

Anyone had experienced the same problem ?

Thanks a lot.