angular-cli: “ng new app” creates project but with some errors

On running ng new app, my directory for app with files and folders seems to be created but with a stack which I am sharing below:

$ ng new music
installing ng
  create .editorconfig
  create README.md
  create src\app\app.component.css
  create src\app\app.component.html
  create src\app\app.component.spec.ts
  create src\app\app.component.ts
  create src\app\app.module.ts
  create src\assets\.gitkeep
  create src\environments\environment.prod.ts
  create src\environments\environment.ts
  create src\favicon.ico
  create src\index.html
  create src\main.ts
  create src\polyfills.ts
  create src\styles.css
  create src\test.ts
  create src\tsconfig.app.json
  create src\tsconfig.spec.json
  create src\typings.d.ts
  create .-cli.json
  create e2e\app.e2e-spec.ts
  create e2e\app.po.ts
  create e2e\tsconfig.e2e.json
  create .gitignore
  create karma.conf.js
  create package.json
  create protractor.conf.js
  create tsconfig.json
  create tslint.json
Installing packages for tooling via npm.
spawn UNKNOWN
Error: spawn UNKNOWN
    at exports._errnoException (util.js:1022:11)
    at ChildProcess.spawn (internal/child_process.js:313:11)
    at exports.spawn (child_process.js:380:9)
    at Object.exports.execFile (child_process.js:143:15)
    at Object.exports.exec (child_process.js:103:18)
    at C:\Users\user\AppData\Roaming\npm\node_modules\@\cli\tasks\npm-install.js:15:29
    at Class.run (C:\Users\user\AppData\Roaming\npm\node_modules\@\cli\tasks\npm-install.js:13:16)
    at C:\Users\user\AppData\Roaming\npm\node_modules\@\cli\tasks\init.js:83:35
    at tryCatch (C:\Users\user\AppData\Roaming\npm\node_modules\@\cli\node_modules\rsvp\dist\rsvp.js:538:12)
    at invokeCallback (C:\Users\user\AppData\Roaming\npm\node_modules\@\cli\node_modules\rsvp\dist\rsvp.js:553:13)
    at publish (C:\Users\user\AppData\Roaming\npm\node_modules\@\cli\node_modules\rsvp\dist\rsvp.js:521:7)
    at flush (C:\Users\user\AppData\Roaming\npm\node_modules\@\cli\node_modules\rsvp\dist\rsvp.js:2373:5)
    at _combinedTickCallback (internal/process/next_tick.js:67:7)
    at process._tickCallback (internal/process/next_tick.js:98:9)

I am not able to figure out why this occurs. The project seems to be running fine without any problem but why this error.

Versions:

@angular/cli: 1.0.0-rc.1
node: 6.9.5
npm: 3.10.10
os: win32 x64