diff --git a/database.cc b/database.cc
index efc38762..70f80f9f 100644
--- a/database.cc
+++ b/database.cc
@@ -479,6 +479,7 @@ notmuch_database_add_message (notmuch_database_t *notmuch,
     GPtrArray *parents, *thread_ids;
 
     const char *refs, *in_reply_to, *date, *header;
+    const char *from, *to, *subject;
     char *message_id;
 
     time_t time_value;
@@ -487,10 +488,12 @@ notmuch_database_add_message (notmuch_database_t *notmuch,
     message = notmuch_message_open (filename);
 
     notmuch_message_restrict_headers (message,
-				      "references",
+				      "date",
+				      "from",
 				      "in-reply-to",
 				      "message-id",
-				      "date",
+				      "references",
+				      "subject",
 				      (char *) NULL);
 
     try {
@@ -567,7 +570,19 @@ notmuch_database_add_message (notmuch_database_t *notmuch,
 	doc.add_value (NOTMUCH_VALUE_DATE,
 		       Xapian::sortable_serialise (time_value));
 
-	db->add_document (doc);
+	from = notmuch_message_get_header (message, "from");
+	subject = notmuch_message_get_header (message, "subject");
+	to = notmuch_message_get_header (message, "to");
+
+	if (from == NULL &&
+	    subject == NULL &&
+	    to == NULL)
+	{
+	    notmuch_message_close (message);
+	    return NOTMUCH_STATUS_FILE_NOT_EMAIL;
+	} else {
+	    db->add_document (doc);
+	}
     } catch (const Xapian::Error &error) {
 	fprintf (stderr, "A Xapian exception occurred: %s.\n",
 		 error.get_msg().c_str());
diff --git a/message.c b/message.c
index 03583c8d..1a5994ff 100644
--- a/message.c
+++ b/message.c
@@ -37,6 +37,8 @@ struct _notmuch_message {
     /* Header storage */
     int restrict_headers;
     GHashTable *headers;
+    int broken_headers;
+    int good_headers;
 
     /* Parsing state */
     char *line;
@@ -234,12 +236,21 @@ notmuch_message_get_header (notmuch_message_t *message,
 	colon = strchr (message->line, ':');
 
 	if (colon == NULL) {
-	    fprintf (stderr, "Warning: Unexpected non-header line: %s\n",
-		     message->line);
+	    message->broken_headers++;
+	    /* A simple heuristic for giving up on things that just
+	     * don't look like mail messages. */
+	    if (message->broken_headers >= 10 &&
+		message->good_headers < 5)
+	    {
+		message->parsing_finished = 1;
+		continue;
+	    }
 	    NEXT_HEADER_LINE (NULL);
 	    continue;
 	}
 
+	message->good_headers++;
+
 	header = xstrndup (message->line, colon - message->line);
 
 	if (message->restrict_headers &&
diff --git a/notmuch.c b/notmuch.c
index 91ea3451..01000c2a 100644
--- a/notmuch.c
+++ b/notmuch.c
@@ -145,6 +145,7 @@ add_files (notmuch_database_t *notmuch, const char *path,
     int err;
     char *next;
     struct stat st;
+    notmuch_status_t status;
 
     dir = opendir (path);
 
@@ -187,8 +188,13 @@ add_files (notmuch_database_t *notmuch, const char *path,
 	stat (next, &st);
 
 	if (S_ISREG (st.st_mode)) {
-	    notmuch_database_add_message (notmuch, next);
-	    state->count++;
+	    status = notmuch_database_add_message (notmuch, next);
+	    if (status == NOTMUCH_STATUS_FILE_NOT_EMAIL) {
+		fprintf (stderr, "Note: Ignoring non-mail file: %s\n",
+			 next);
+	    } else {
+		state->count++;
+	    }
 	    if (state->count % 1000 == 0)
 		add_files_print_progress (state);
 	} else if (S_ISDIR (st.st_mode)) {
@@ -293,9 +299,10 @@ setup_command (int argc, char *argv[])
     printf ("Notmuch needs to know the top-level directory of your email archive,\n"
 	    "(where you already have mail stored and where messages will be delivered\n"
 	    "in the future). This directory can contain any number of sub-directories\n"
-	    "but the only files it contains should be individual email messages.\n"
-	    "Either maildir or mh format directories are fine, but you will want to\n"
-	    "move away any auxiliary files maintained by other email programs.\n\n");
+	    "and primarily just files with indvidual email messages (eg. maildir or mh\n"
+	    "archives are perfect). If there are other, non-email files (such as\n"
+	    "indexes maintained by other email programs) then notmuch will do its\n"
+	    "best to detect those and ignore them.\n\n");
 
     printf ("Mail storage that uses mbox format, (where one mbox file contains many\n"
 	    "messages), will not work with notmuch. If that's how your mail is currently\n"
diff --git a/notmuch.h b/notmuch.h
index 873c88d2..e0b57db2 100644
--- a/notmuch.h
+++ b/notmuch.h
@@ -40,10 +40,14 @@ NOTMUCH_BEGIN_DECLS
  * NOTMUCH_STATUS_SUCCESS: No error occurred.
  *
  * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred
+ *
+ * NOTMUCH_STATUS_FILE_NOT_EMAIL: A file was presented that doesn't
+ * 	appear to be an email message.
  */
 typedef enum _notmuch_status {
     NOTMUCH_STATUS_SUCCESS = 0,
-    NOTMUCH_STATUS_XAPIAN_EXCEPTION
+    NOTMUCH_STATUS_XAPIAN_EXCEPTION,
+    NOTMUCH_STATUS_FILE_NOT_EMAIL
 } notmuch_status_t;
 
 /* An opaque data structure representing a notmuch database. See
@@ -116,7 +120,15 @@ notmuch_database_get_path (notmuch_database_t *database);
  * single mail message (not a multi-message mbox) that is expected to
  * remain at its current location, (since the notmuch database will
  * reference the filename, and will not copy the entire contents of
- * the file. */
+ * the file.
+ *
+ * Return value:
+ *
+ * NOTMUCH_STATUS_SUCCESS: Message successfully added to database.
+ *
+ * NOTMUCH_STATUS_FILE_NOT_EMAIL: the contents of filename don't look
+ * 	like an email message. Nothing added to the database.
+ */
 notmuch_status_t
 notmuch_database_add_message (notmuch_database_t *database,
 			      const char *filename);