6.5.4 A note on namespaces

The IMAP protocol has a concept called namespaces, described by the following text in the RFC:

5.1.2. Mailbox Namespace Naming Convention By convention, the first hierarchical element of any mailbox name which begins with "#" identifies the "namespace" of the remainder of the name. This makes it possible to disambiguate between different types of mailbox stores, each of which have their own namespaces. For example, implementations which offer access to USENET newsgroups MAY use the "#news" namespace to partition the USENET newsgroup namespace from that of other mailboxes. Thus, the comp.mail.misc newsgroup would have an mailbox name of "#news.comp.mail.misc", and the name "comp.mail.misc" could refer to a different object (e.g. a user's private mailbox).

While there is nothing in this text that warrants concern for the IMAP implementation in Gnus, some servers use namespace prefixes in a way that does not work with how Gnus uses mailbox names.

Specifically, University of Washington's IMAP server uses mailbox names like #driver.mbx/read-mail which are valid only in the CREATE and APPEND commands. After the mailbox is created (or a messages is appended to a mailbox), it must be accessed without the namespace prefix, i.e read-mail. Since Gnus do not make it possible for the user to guarantee that user entered mailbox names will only be used with the CREATE and APPEND commands, you should simply not use the namespace prefixed mailbox names in Gnus.

See the UoW IMAPD documentation for the #driver.*/ prefix for more information on how to use the prefixes. They are a power tool and should be used only if you are sure what the effects are.