[Dovecot] Thunderbird problem

Hello

Some users had occasionally a problem with Thunderbird , some random emails with attachement(s) cannot be read anymore the email appears empty and TB seems to enter in an infinite loop saying it is downloading the message

The only solution I found was :

1 - stop thunderbird on the client machine 2 - remove the .imap user's directory 3 - restart thunderbird on the client machine

After doing that all emails re-appear normally and attachements are readable/downloadable again.

ALL our clients use the IMAP(S) protocol.

Anyone had the same problem ?

Thanks F