Q:

Erro tentar executar o app com ionic serve

Ao tentar executar o app com ionic serve esta dando o seguinte erro:
> ionic-hello-world@ ionic:serve D:\www\mobile\app
> ionic-app-scripts serve "--v2" "undefined" "--address" "0.0.0.0" "--port" "810
0" "--livereload-port" "35729"

[23:00:51]  ionic-app-scripts 1.1.0
[23:00:51]  watch started ...
[23:00:51]  build dev started ...
[23:00:51]  clean started ...
[23:00:51]  clean finished in less than 1 ms
[23:00:51]  copy started ...
[23:00:51]  transpile started ...
[23:00:57]  transpile finished in 6.60 s
[23:00:57]  preprocess started ...
[23:00:57]  preprocess finished in less than 1 ms
[23:00:57]  webpack started ...
[23:00:58]  copy finished in 7.13 s
[23:01:05]  webpack finished in 8.09 s
[23:01:05]  sass started ...
[23:01:07]  sass finished in 1.15 s
[23:01:07]  postprocess started ...
[23:01:07]  postprocess finished in 1 ms
[23:01:07]  lint started ...
[23:01:07]  build dev finished in 16.03 s
[23:01:10]  watch failed: A watch configured to watch the following paths failed
 to start. It likely that a file
            referenced does not exist: D:\www\mobile\app\src\**\*.(ts|html|s(c|a
)ss)
[23:01:10]  dev server running: http://localhost:8100/

[23:01:16]  lint finished in 9.63 s

Erro:

[23:01:10]  watch failed: A watch configured to watch the following
  paths failed  to start. It likely that a file
              referenced does not exist: D:\www\mobile\app\src***.(ts|html|s(c|a )ss)

A:

Resolvido:
npm install @ionic/app-scripts@latest --save-dev

