diff --git a/rpm_spec/core-vm.spec b/rpm_spec/core-vm.spec
index 0c576bf..f1a5e5d 100644
--- a/rpm_spec/core-vm.spec
+++ b/rpm_spec/core-vm.spec
@@ -328,9 +328,13 @@ mkdir -p /rw
 %preun
 if [ "$1" = 0 ] ; then
     # no more packages left
+    if [ -e /var/lib/qubes/fstab.orig ] ; then
     mv /var/lib/qubes/fstab.orig /etc/fstab
+    fi
     mv /var/lib/qubes/removed-udev-scripts/* /etc/udev/rules.d/
+    if [ -e /var/lib/qubes/serial.orig ] ; then
     mv /var/lib/qubes/serial.orig /etc/init/serial.conf
+    fi
 fi
 
 %postun