Turbopack Error: Resource path "src/app/not-found.tsx" need to be on project filesystem ""

[Abdelrahman-Mahana]

Turbopack version: d1bd5b58
Next.js version: 0.0.0

Error message:

Resource path "src/app/not-found.tsx" need to be on project filesystem ""

Debug info:
- Execution of hmr_update_with_issues_operation failed
- Execution of PlainIssue::from_issue failed
- Execution of PlainSource::from_source failed
- Execution of <WebpackLoadersProcessedAsset as Asset>::content failed
- Execution of WebpackLoadersProcessedAsset::process failed
- Resource path "src/app/not-found.tsx" need to be on project filesystem ""

[azamxvit]

This error usually means that Turbopack cannot correctly detect the project filesystem root and ends up treating src/app/not-found.tsx as if it were outside of the project.

First, make sure you are running the dev server from the actual Next.js project root. The directory where you run next dev should contain package.json, next.config.js (or next.config.mjs), and the src/ folder if you’re using the src directory. Running the command from a parent or nested folder often causes this exact error.

Also double-check that you are really using the App Router. The not-found.tsx file is only supported in the App Router (app/ or src/app). If the project is using the Pages Router, this file will not be recognized correctly.

Another thing to look at is your next.config. Custom setups like monorepos, workspaces, or options such as distDir can confuse Turbopack if the project root does not match the location of src/app.

One thing that stands out is:

Next.js version: 0.0.0

This usually means the version could not be resolved properly or Next.js is being run from source. Reinstalling dependencies and making sure you are using an official Next.js release often fixes this.

As a quick workaround, you can try running the dev server with Webpack:

next dev --webpack

If that works, it confirms this is a Turbopack-specific issue rather than a problem with the file itself.

Overall, this doesn’t look like an issue with not-found.tsx, but rather a project root / filesystem detection problem in Turbopack.

[nextjs-bot]

This discussion appears to be a duplicate of #88177.

Please follow the discussion there: #88177

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