diff -up evolution-3.8.5/modules/settings/e-settings-mail-formatter.c.crash-mail-header-show evolution-3.8.5/modules/settings/e-settings-mail-formatter.c
--- evolution-3.8.5/modules/settings/e-settings-mail-formatter.c.crash-mail-header-show	2014-08-25 17:24:50.317186665 +0200
+++ evolution-3.8.5/modules/settings/e-settings-mail-formatter.c	2014-08-25 17:24:50.323186664 +0200
@@ -67,13 +67,13 @@ settings_mail_formatter_headers_changed_
 	if (key) {
 		GSList *link;
 
-		for (ii = 0, link = extension->priv->old_headers; headers && headers[ii]; ii++, link = g_slist_next (link)) {
+		for (ii = 0, link = extension->priv->old_headers; link && headers && headers[ii]; ii++, link = g_slist_next (link)) {
 			if (g_strcmp0 (link->data, headers[ii]) != 0)
 				break;
 		}
 
 		/* both lists are read to the end, thus they are the same */
-		if (!headers[ii] && !link) {
+		if ((!headers || !headers[ii]) && !link) {
 			g_strfreev (headers);
 			return;
 		}