diff --git a/update_psa b/update_psa
index 75a34b6..cb6c10f 100755
--- a/update_psa
+++ b/update_psa
@@ -70,7 +70,19 @@ while test $# -gt 0; do
     esac
     shift
 done
-    
+   
+if [ -z "$WORKING_DIRECTORY" ]; then
+    echo "WORKING_DIRECTORY empty. exiting..."
+    exit 1    
+fi
+
+if [ ! -d "$WORKING_DIRECTORY" ]; then
+    echo "WORKING_DIRECTORY $WORKING_DIRECTORY does not exist! exiting..."
+    exit 1
+fi
+
+cd "$WORKING_DIRECTORY"
+
 source ./update_psa_impl
 
 if read_config; then