Index: Mk/Scripts/check_leftovers.sh
===================================================================
--- Mk/Scripts/check_leftovers.sh
+++ Mk/Scripts/check_leftovers.sh
@@ -109,6 +109,9 @@
 			# Leave qmail's queue dir alone to not cause lost mail
 			# during upgrades, just as /var/mail is left alone.
 			/var/qmail/queue/*|/var/qmail/queue) continue ;;
+			# Leave machine-id generated by D-Bus alone. This file
+			# prevents some programs like Firefox from crashing.
+			/var/lib/dbus/machine-id) continue ;;
 		esac
 
 		# Check relative/plist paths
Index: devel/dbus/Makefile
===================================================================
--- devel/dbus/Makefile
+++ devel/dbus/Makefile
@@ -3,7 +3,7 @@
 
 PORTNAME=	dbus
 DISTVERSION=	1.12.20
-PORTREVISION=	3
+PORTREVISION=	4
 CATEGORIES=	devel gnome
 MASTER_SITES=	http://dbus.freedesktop.org/releases/dbus/
 
@@ -39,11 +39,14 @@
 PLIST_SUB=	GROUPS=${GROUPS} \
 		VERSION="1.0"
 
-OPTIONS_DEFINE=		EXAMPLES MANPAGES X11
-OPTIONS_DEFAULT=	MANPAGES X11
+OPTIONS_DEFINE=		EXAMPLES MACHINEID MANPAGES X11
+OPTIONS_DEFAULT=	MACHINEID MANPAGES X11
 OPTIONS_SUB=		yes
+MACHINEID_DESC=		Ensure /var/lib/dbus/machine-id during installation
 X11_DESC=		Support X11 Desktop Environments
 
+MACHINEID_SUB_FILES=		pkg-install
+MACHINEID_VARS=			PKGINSTALL=${WRKDIR}/pkg-install
 MANPAGES_BUILD_DEPENDS=		minixmlto:textproc/minixmlto
 MANPAGES_CONFIGURE_ENABLE=	xml-docs
 MANPAGES_CONFIGURE_ENV=		XMLTO=${LOCALBASE}/bin/minixmlto
Index: devel/dbus/files/pkg-install.in
===================================================================
--- /dev/null
+++ devel/dbus/files/pkg-install.in
@@ -0,0 +1,10 @@
+#! /bin/sh -
+# $FreeBSD$
+
+: "${PKG_ROOTDIR:=/}"
+: "${PKG_PREFIX:=%%PREFIX%%}"
+
+case "$2" in
+POST-INSTALL)
+	${PKG_PREFIX}/bin/dbus-uuidgen --ensure="${PKG_ROOTDIR}/var/lib/dbus/machine-id"
+esac