yarnpkg/yarn · error · MessageError

manifestNameIllegalChars

Error message

manifestNameIllegalChars

What it means

Error "manifestNameIllegalChars" thrown in yarnpkg/yarn.

Solutions

1. Remove the illegal characters from the package name. npm names may only contain lowercase letters, numbers, hyphens, underscores, and dots (no leading dot), plus an optional @scope/ prefix. Edit the name field in package.json.

Example fix

"name": "My Package!" -> "my-package"

When it happens

Trigger: A manifest name contains illegal URL or filesystem characters during normalization validation in src/util/normalize-manifest/validate.js.

Common situations: Occurs when package.json 'name' contains characters such as spaces, uppercase in some registries, or symbols disallowed by npm naming rules.

AI-assisted analysis of yarnpkg/yarn@c2dda503f3 (2026-08-13). Data as JSON: /api/errors/0f1cca5e962e1590. Report an issue: GitHub.

Appendix: source

Thrown at src/util/normalize-manifest/validate.js:67

      }
    }
  }

  // validate name
  const {name} = info;
  if (typeof name === 'string') {
    if (isRoot && isBuiltinModule(name)) {
      warn(reporter.lang('manifestBuiltinModule', name));
    }

    // cannot start with a dot
    if (name[0] === '.') {
      throw new MessageError(reporter.lang('manifestNameDot'));
    }

    // cannot contain the following characters
    if (!isValidPackageName(name)) {
      throw new MessageError(reporter.lang('manifestNameIllegalChars'));
    }

    // cannot equal node_modules or favicon.ico
    const lower = name.toLowerCase();
    if (lower === 'node_modules' || lower === 'favicon.ico') {
      throw new MessageError(reporter.lang('manifestNameBlacklisted'));
    }
  }

  // validate license
  if (isRoot && !info.private) {
    if (typeof info.license === 'string') {
      const license = info.license.replace(/\*$/g, '');
      if (!isValidLicense(license)) {
        warn(reporter.lang('manifestLicenseInvalid'));
      }
    } else {
      warn(reporter.lang('manifestLicenseNone'));

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