diff --git a/packages-update b/packages-update
index 0e0a87f..9a524e1 100644
--- a/packages-update
+++ b/packages-update
@@ -6,6 +6,9 @@
 
 :global DownloadPackage;
 :global ScriptFromTerminal;
+:global ScriptLock;
+
+$ScriptLock "packages-update";
 
 :local Update [ / system package update get ];