diff --git a/packages/electron/main.mjs b/packages/electron/main.mjs
index 9ecbead7..0442f814 100644
--- a/packages/electron/main.mjs
+++ b/packages/electron/main.mjs
@@ -1240,7 +1240,15 @@ const registerPackagedUiProtocol = () => {
         if (filePath.endsWith('.html')) {
           const html = await fsp.readFile(filePath, 'utf8');
           const body = injectRuntimeConfigIntoHtml(html);
-          return new Response(body, { headers: { 'Content-Type': 'text/html; charset=utf-8' } });
+          // index.html must never be cached: it names the hashed asset
+          // bundles, and a cached copy keeps a freshly installed build
+          // loading the previous version's UI from the renderer disk cache.
+          return new Response(body, {
+            headers: {
+              'Content-Type': 'text/html; charset=utf-8',
+              'Cache-Control': 'no-store',
+            },
+          });
         }
         return electronNet.fetch(pathToFileURL(filePath).toString());
       }