tauri-apps/tauri · error

Missing OS permission to access path

Error message

Missing OS permission to access path "{path}": {e}

What it means

A PermissionDenied io error while opening the asset file means the OS refused access (file mode, ACLs, sandboxing, or missing Android storage permission). The handler logs this message and returns HTTP 403 with an empty body.

Solutions

  1. Fix OS-level permissions on the file/directory (chmod/chown or ACLs) so the app process can read it
  2. On Android, declare and request storage permissions at runtime (or use the app's private storage)
  3. Pick a source location the app can read (app data dir) or expose the file through a custom command with elevated handling

Example fix

// before (Android)
let path = "/storage/emulated/0/DCIM/photo.jpg"; // needs runtime permission
// after
// request READ_MEDIA_IMAGES / storage permission first, or copy into app storage
let path = app_data_dir.join("cache/photo.jpg");
Defensive patterns

Strategy: fallback

Validate before calling

// Rust-side pre-check before serving
std::fs::File::open(&path).map_err(|e| e.to_string())?; // fail early with a clear message

Type guard

function canRead(p: string): boolean {
  try { fs.accessSync(p, fs.constants.R_OK); return true; } catch { return false; }
}

Try / catch

const resp = await fetch(assetUrl);
if (resp.status === 403) {
  // ask user to grant permission / move file into app-accessible location
  await invoke('request_storage_permission');
}

Prevention

When it happens

Trigger: File::open(path) inside get_response returns std::io::ErrorKind::PermissionDenied — e.g. restrictive file permissions, the process sandbox denies the path, or on Android external storage is accessed without READ_EXTERNAL_STORAGE / storage permission.

Common situations: Serving files from another user's home directory on Linux/macOS; Windows ACLs blocking the service account; Android scoped storage (no MANAGE_EXTERNAL_STORAGE or legacy storage flag) when reading shared storage.

Understand the failure class

Background: "You do not have permission" / 403 Forbidden errors: authenticated but not allowed — causes and fixes across open-source libraries — this error's family across 31 libraries.

Related errors

AI-assisted analysis of tauri-apps/tauri@460ec35447 (2026-09-18). Data as JSON: /api/errors/878f817eb1452eab. Report an issue: GitHub.

Appendix: source

Thrown at crates/tauri/src/protocol/asset.rs:68

  // Separate block for easier error handling
  let mut file = match File::open(path.clone()) {
    Ok(file) => file,
    Err(e) => {
      #[cfg(target_os = "android")]
      {
        if path.starts_with("/storage/emulated/0/Android/data/") {
          log::error!(
            "Failed to open Android external storage file '{path}': {e}. This may be due to missing storage permissions."
          );
        }
      }
      return if e.kind() == std::io::ErrorKind::NotFound {
        log::error!("File does not exist at path: {path}");
        return resp.status(404).body(Vec::new().into()).map_err(Into::into);
      } else if e.kind() == std::io::ErrorKind::PermissionDenied {
        log::error!("Missing OS permission to access path \"{path}\": {e}");
        return resp.status(403).body(Vec::new().into()).map_err(Into::into);
      } else {
        Err(e.into())
      };
    }
  };

  let len = file.metadata()?.len();
  let (mime_type, read_bytes) = {
    // get file mime type
    let nbytes = len.min(8192);
    let mut magic_buf = Vec::with_capacity(nbytes as usize);
    (&mut file).take(nbytes).read_to_end(&mut magic_buf)?;
    file.rewind()?;
    (
      MimeType::parse(&magic_buf, &path),
      // return the `magic_bytes` if we read the whole file
      // to avoid reading it again later if this is not a range request
      if len < 8192 { Some(magic_buf) } else { None },

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