npm run build error

$ npm run build

> iview-admin@1.3.1 build C:\Users\dn\Desktop\iview-admin-dev
> webpack --progress --hide-modules --config build/webpack.prod.config.js

clean-webpack-plugin: C:\Users\dn\Desktop\iview-admin-dev\dist\* has been removed.
Happy[happybabel]: Version: 4.0.1. Threads: 4 (shared pool)
(node:8844) [DEP0013] DeprecationWarning: Calling an asynchronous function without callback is deprecated.
internal/child_process.js:323
throw errnoException(err, 'spawn');
^

Error: spawn EBUSY
at _errnoException (util.js:1022:11)
at ChildProcess.spawn (internal/child_process.js:323:11)
at exports.spawn (child_process.js:502:9)
at exports.fork (child_process.js:103:10)
at open (C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\lib\HappyThread.js:45:12)
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:713:13
at async.forEachOf.async.eachOf (C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:233:13)
at _parallel (C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:712:9)
at Object.async.parallel (C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:726:9)
at Object.start (C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\lib\HappyThreadPool.js:60:13)
at launchAndConfigureThreads (C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\lib\HappyPlugin.js:172:23)
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:713:13
at iterate (C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:262:13)
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:274:29
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:44:16
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:718:17
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:167:37
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\lib\HappyPlugin.js:154:9
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:721:13
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:52:16
at done (C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:246:17)
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:44:16
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:718:17
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\node_modules\async\lib\async.js:167:37
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\happypack\lib\WebpackUtils.js:185:16
at onResolve (C:\Users\dn\Desktop\iview-admin-dev\node_modules\enhanced-resolve\lib\Resolver.js:70:11)
at innerCallback (C:\Users\dn\Desktop\iview-admin-dev\node_modules\enhanced-resolve\lib\Resolver.js:143:22)
at callbackWrapper (C:\Users\dn\Desktop\iview-admin-dev\node_modules\enhanced-resolve\lib\createInnerCallback.js:10:21)
at next (C:\Users\dn\Desktop\iview-admin-dev\node_modules\tapable\lib\Tapable.js:249:35)
at C:\Users\dn\Desktop\iview-admin-dev\node_modules\enhanced-resolve\lib\UnsafeCachePlugin.js:39:22
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! iview-admin@1.3.1 build: `webpack --progress --hide-modules --config build/webpack.prod.config.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the iview-admin@1.3.1 build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR! C:\Users\dn\AppData\Roaming\npm-cache\_logs\2018-04-27T11_52_11_448Z-debug.log

Start by running npm run build and inspect build/webpack.prod.config.js, focusing on the HappyPack thread-spawn stack shown in the report. Reproduce the Windows spawn EBUSY failure and confirm that the build completes successfully without the reported error.

Written by the indexing model from the issue text.