Something I've done but not yet identified has hosed my working-for-years Gnus<->offlineimap<->GMail setup. Gnus gives me a bunch of errors like:
Warning - invalid active: [Gmail].Starred 26 2 y
for each of the 8 standard GMail folders being synced (Sent, Important, Trash, Spam, All Mail, Bin, Starred, and Drafts) and presents a *Group* buffer consisting of nothing but:
4: nndraft:drafts
instead of the dozens of subscribed groups (mail folders) I expect to see.
I find no relevant matches for 'invalid' in the Gnus manual, nor anything in multiple web searches.
One piece of context: after this first happened, I checked my offlineimap logs and found there were a lot of folder UID errors, so I completely rebuilt my offlineimap local repo from scratch, which took almost 48 hours.
Possibly relevant Gnus user options:
'(gnus-article-sort-functions
(quote
((not gnus-article-sort-by-number))))
'(gnus-check-new-newsgroups nil)
'(gnus-extract-address-components
(quote mail-extract-address-components))
'(gnus-home-directory "~/.emacs.d/gnus/")
'(gnus-ignored-newsgroups "^to\\.\\|^[0-9. ]+\\( \\|$\\)\\|^[\"]\"[#'()]")
'(gnus-init-file "~/.emacs.d/.gnus.el")
'(gnus-large-newsgroup nil)
'(gnus-parameters
(quote
((".*"
(visible . t))
("INBOX"
(display . 75))
("All Mail"
(display . 75)))))
'(gnus-read-active-file nil)
'(gnus-read-newsrc-file nil)
'(gnus-save-killed-list nil)
'(gnus-save-newsrc-file nil)
'(gnus-select-method
(quote
(nnmaildir "GMail"
(directory "~/GMail/")
(directory-files nnheader-directory-files-safe)
(get-new-mail nil))))
'(gnus-started-hook
(quote
(ph/gnus-redisplay-groups ph/setup-bbdb)))
'(gnus-startup-hook
(quote
(bbdb-insinuate-gnus)))
'(gnus-subscribe-newsgroup-method
(quote gnus-subscribe-alphabetically))
'(gnus-thread-sort-functions
(quote
((not gnus-thread-sort-by-number)
(not gnus-thread-sort-by-date))))
'(gnus-use-scoring nil)
Edit: gnus-version is "Gnus v5.13" and emacs-version is "24.5.1"