diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index 311c18db0..842997448 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -174,6 +174,20 @@ pnpm dev:tamagotchi
 > nr dev:tamagotchi
 > ```
 
+> [!NOTE]
+>
+> The `dev` and `start` scripts run `install-electron` before `electron-vite`.
+>
+> Electron 42 removed the `postinstall` script. The `electron` package now downloads its binary
+> when you first run its `bin` entry. `electron-vite` reads `node_modules/electron/path.txt`
+> directly, so it never starts that download. A fresh install therefore fails with
+> `Error: Electron uninstall`.
+>
+> `install-electron` runs the same code as the removed `postinstall` script. It returns
+> immediately when the binary is already present.
+>
+> Remove this step after `electron-vite` supports the lazy download.
+
 ### Stage Web (Browser version for [airi.moeru.ai](https://airi.moeru.ai))
 
 ```shell
diff --git a/apps/stage-tamagotchi/package.json b/apps/stage-tamagotchi/package.json
index 22102642a..8d1b4928e 100644
--- a/apps/stage-tamagotchi/package.json
+++ b/apps/stage-tamagotchi/package.json
@@ -16,10 +16,10 @@
     "typecheck": "vue-tsc --noEmit",
     "app:dev": "pnpm run dev",
     "app:build": "pnpm run build",
-    "start": "electron-vite preview",
-    "start:xwayland": "electron-vite preview -- --ozone-platform=x11",
-    "dev": "electron-vite dev",
-    "dev:xwayland": "electron-vite dev -- --ozone-platform=x11",
+    "start": "install-electron && electron-vite preview",
+    "start:xwayland": "install-electron && electron-vite preview -- --ozone-platform=x11",
+    "dev": "install-electron && electron-vite dev",
+    "dev:xwayland": "install-electron && electron-vite dev -- --ozone-platform=x11",
     "build": "electron-vite build",
     "postinstall": "electron-builder install-app-deps",
     "build:unpack": "pnpm run build && electron-builder --dir",