---
title: 'Experimental `appDir: true`'
---

## Why This Error Occurred

Your project contains a directory named `app/`. Since Next.js 13, this is a [reserved name](/blog/next-13#new-app-directory-beta).

## Possible Ways to Fix It

To use the new app directory and its features, please add `appDir: true` to your configuration in `next.config.js` under `experimental`.

```js filename="next.config.js"
/** @type {import('next').NextConfig} */
const nextConfig = {
  experimental: {
    appDir: true,
  },
}

module.exports = nextConfig
```

If you do not want to use the new `app/` directory features yet, but have a directory named `app/`, rename the directory to something else.

## Useful Links

- [Next.js 13 App directory](/blog/next-13#new-app-directory-beta)
- [App directory documentation](/docs/app/building-your-application)