diff --git a/src/main/ts/i18n.ts b/src/main/ts/i18n.ts
--- a/src/main/ts/i18n.ts
+++ b/src/main/ts/i18n.ts
@@ -22,7 +22,7 @@ export function bundle<T extends object>
     fn.define = (pack: Partial<T>) => pack;
     fn.default = nlsBundle.default;
     fn.load = async (id: string, require: Require, cb: OnLoad, config: any) => {
-        if (config.isBuild) {
+        if (config && config.isBuild) {
             cb();
         } else {
             try {