diff --git a/scripts/build-dist.mjs b/scripts/build-dist.mjs
index 0153dd4a..b30f1167 100644
--- a/scripts/build-dist.mjs
+++ b/scripts/build-dist.mjs
@@ -38,7 +38,8 @@ function copyFile(src, dest) {
   if (fs.existsSync(src)) {
     fs.copyFileSync(src, dest);
   } else {
-    console.warn(`Warning: Source file ${src} does not exist.`);
+    console.error(`Error: Source file ${src} does not exist.`);
+    process.exit(1);
   }
 }