diff --git a/apsalar/icloudsync b/apsalar/icloudsync
index a5a27fc..a5a4b65 100755
--- a/apsalar/icloudsync
+++ b/apsalar/icloudsync
@@ -9,6 +9,17 @@ if ! type icloudpd >/dev/null; then
     exit 1
 fi
 
+# Ensure environment variables are set
+if [[ -z "$ICLOUD_DIR" ]]; then
+  echo 'please set $ICLOUD_DIR'
+  exit 1
+fi
+
+if [[ -z "$ICLOUD_USERNAME" ]]; then
+  echo 'please set $ICLOUD_USERNAME'
+  exit 1
+fi
+
 # tmux session name
 session="icloudsync"