I installed notmuch from debian testing and it seems to work OK (from the command line), e.g.
newmail at argo:~$ notmuch search blabla thread:0000000000000001 Yest. 22:56 [1/1] fldsj at falma.de; blabla (inbox unread) The maildir contains just one message. Now I start up emacs, eval (require 'notmuch) and say M-x notmuch Emacs now shows a buffer with the following contents Welcome to notmuch. You have And displays the following messages Visit the notmuch website. process-lines: notmuch exited with status 1 Clearly I am missing something trivial here, but I fail to find out what. Thanks, Christoph