Turbopack Error: Failed to write app endpoint /page

[MaenAbabneh]

Turbopack version: `v16.0.0-beta.0` Next.js version: `0.0.0`

Error message:

Failed to write app endpoint /page

Caused by:
- [project]/app/globals.css [app-client] (css)
- Item already exists

Debug info:
- Execution of get_written_endpoint_with_issues_operation failed
- Execution of endpoint_write_to_disk failed
- Execution of <AppEndpoint as Endpoint>::output failed
- Failed to write app endpoint /page
- Execution of AppEndpoint::output failed
- Execution of AppProject::app_module_graphs failed
- Execution of *<AppEndpoint as Endpoint>::additional_entries failed
- Execution of *ModuleGraph::from_graphs failed
- Execution of SingleModuleGraph::new_with_entries_visited_intern failed
- [project]/app/globals.css [app-client] (css)
- Execution of primary_chunkable_referenced_modules failed
- Execution of <CssModuleAsset as Module>::references failed
- Execution of parse_css failed
- Execution of <PostCssTransformedAsset as Asset>::content failed
- Execution of PostCssTransformedAsset::process failed
- Execution of evaluate_webpack_loader failed
- Item already exists

[MaenAbabneh]

i think new "turbopackFileSystemCacheForDev"
is because many time had problem with it !

[DanielSalazarLoaiza]

It looks like this error happens when Turbopack tries to write the same file twice, usually app/globals.css.

Here’s what worked for me:

1. Make sure globals.css is only imported once, ideally in your root app/layout.tsx.

2. Delete any duplicate routes like

app/page.tsx
app/page/index.tsx

3. Clear the cache:

rm -rf .next

and restart the dev server.

4. If it still happens, try running with Webpack to confirm it’s Turbopack-related:

NEXT_USE_TURBOPACK=0 npm run dev

5. (Optional) Update to the latest canary version — this issue has been actively patched in recent builds.

If none of that helps, you can also try adding this in your next.config.js to avoid duplicate CSS resolution:

experimental: {
  turbo: {
    resolveAlias: {
      './globals.css': false,
    },
  },
},

It’s a known conflict between Turbopack’s virtual FS and CSS module resolution — likely fixed soon in the next beta.