diff --git a/modules/system/upstart-events/halt.nix b/modules/system/upstart-events/halt.nix
index 60727e3686b..82b5ffcae1a 100644
--- a/modules/system/upstart-events/halt.nix
+++ b/modules/system/upstart-events/halt.nix
@@ -69,7 +69,12 @@ let
               for mp in $(getMountPoints); do
                   device=$(getDevice $mp)
                   echo "unmounting $mp..."
-                  if umount -f -n "$mp"; then
+                  # !!! Don't unmount /nix/store or /hostfs.  This is
+                  # a quick hack to cleanly shutdown VMs that mount
+                  # the Nix store via CIFS.  "mount -f" will actually
+                  # work on such filesystems, which makes all commands
+                  # needed below disappear.
+                  if test "$mp" != /nix/store -a "$mp" != /hostfs && umount -f -n "$mp"; then
                       if test "$mp" != /; then tryAgain=1; fi
                   else
                       mount -n -o remount,ro "$mp" || true
diff --git a/modules/tasks/network-interfaces.nix b/modules/tasks/network-interfaces.nix
index 4c57b48bd94..d075d04ed6b 100644
--- a/modules/tasks/network-interfaces.nix
+++ b/modules/tasks/network-interfaces.nix
@@ -159,10 +159,10 @@ in
       respawn sleep 100000
 
       stop script
-          for i in $(cd /sys/class/net && ls -d *); do
-              echo "Taking down network device $i..."
-              ${nettools}/sbin/ifconfig $i down || true
-          done
+          #for i in $(cd /sys/class/net && ls -d *); do
+          #    echo "Taking down network device $i..."
+          #    ${nettools}/sbin/ifconfig $i down || true
+          #done
       end script
     '';
   }];