diff --git a/z.sh b/z.sh
index 187284c..4527a78 100644
--- a/z.sh
+++ b/z.sh
@@ -22,11 +22,6 @@
 #   * z -l foo  # list matches instead of cd
 #   * z -c foo  # restrict matches to subdirs of $PWD
 
-case $- in
- *i*) ;;
-   *) echo 'ERROR: z.sh is meant to be sourced, not directly executed.'
-esac
-
 [ -d "${_Z_DATA:-$HOME/.z}" ] && {
     echo "ERROR: z.sh's datafile (${_Z_DATA:-$HOME/.z}) is a directory."
 }
@@ -80,7 +75,7 @@ _z() {
   if [ $? -ne 0 -a -f "$datafile" ]; then
    env rm -f "$tempfile"
   else
-   env mv -f "$tempfile" "$datafile"
+   env mv -f "$tempfile" "$datafile" || env rm -f "$tmpfile"
   fi
 
  # tab completion