Hi everyone,
I found the Solution myself. The key was to simply create an unnamed mailbox directive so that the namespace prefix directly results into an mailbox that Thunderbirds shows as the Archive.
Thanks everbody on the dovecot team for making such a brilliant Software! Greetings! Christian
namespace inbox { inbox = yes location = mailbox Drafts { auto = subscribe special_use = \Drafts } mailbox Junk { auto = subscribe special_use = \Junk } mailbox Sent { auto = subscribe special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { auto = subscribe special_use = \Trash } prefix = separator = / }
namespace archivns { prefix = Archive/ <--- this is the Name which now appears at the same Level then Sent/Draft/... location = maildir:/mnt/mails2/%u separator = / mailbox { <--- here a name is omitted auto = subscribe special_use = \Archive } }