Error ionic serve "watch failed"

c:\Users\leanovo\fong>ionic serve

ionic-hello-world@ ionic:serve c:\Users\leanovo\fong
ionic-app-scripts serve
[18:04:45] ionic-app-scripts 1.1.3
[18:04:46] watch started …
[18:04:46] build dev started …
[18:04:46] clean started …
[18:04:46] clean finished in 466 ms
[18:04:46] copy started …
[18:04:47] transpile started …
[18:05:56] transpile finished in 68.87 s
[18:05:56] preprocess started …
[18:05:56] preprocess finished in less than 1 ms
[18:05:56] webpack started …
[18:06:16] copy finished in 90.00 s
[18:07:25] webpack finished in 89.02 s
[18:07:25] sass started …
[18:07:59] sass finished in 34.60 s
[18:07:59] postprocess started …
[18:07:59] postprocess finished in 1 ms
[18:07:59] lint started …
[18:08:00] build dev finished in 194.03 s
[18:08:08] watch failed: A watch configured to watch the following paths failed to start. It likely that a file
referenced does not exist: c:\Users\leanovo\fong\src***.(ts|html|s(c|a)ss)
[18:08:08] dev server running: http://localhost:8100/

but app is not error to run
and I have a question : I build android and I try to run .apk ,it not working like run on ionic serve.
Why???