WebpackOptionsValidationError: Invalid configuration object.

[si2030]

Tried both methods of installation... copying files and yo...

Either way I get this error when I run npm start.

`Starting 'start'...
Starting 'clean'...
Finished 'clean' after 0ms
Starting 'appsettings'...
Finished 'appsettings' after 0ms
WebpackOptionsValidationError: Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema.

• configuration has an unknown property 'postcss'. These properties are valid:
  object { amd?, bail?, cache?, context?, dependencies?, devServer?, devtool?, entry, externals?, loader?, module?, name?, node?, output?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, stats?, target?, watch?, watchOptions? }
  For typos: please correct them.
  For loader options: webpack 2 no longer allows custom properties in configuration.
  Loaders should be updated to allow passing options via loader options in module.rules.
  Until loaders are updated one can use the LoaderOptionsPlugin to pass these options to the loader:
  plugins: {
  new webpack.LoaderOptionsPlugin({
  // test: /.xxx$/, // may apply this only for some modules
  options: {
  postcss: ...
  }
  })
  }
  at webpack (C:\Users\simon\REACT\ASPNET CORE REACT REDUX STARTER KIT\STARTER KIT CLONE\node_modules\webpack\lib\webpack.js:16:9)
  at resolve (C:\Users\simon\REACT\ASPNET CORE REACT REDUX STARTER KIT\STARTER KIT CLONE\run.js:159:24)
  at Promise.resolve.then.then.then (C:\Users\simon\REACT\ASPNET CORE REACT REDUX STARTER KIT\STARTER KIT CLONE\run.js:156:17)

I have what I would consider a bog standard windows 10 system. I am using node.js v 6.6.0 and npm 3.10.8

I have no idea how to fix this...

[NullReferenceError]

This issue is the same as this one:

#21

You'll need to install an earlier version of Webpack, or fix the references to postcss in webpack.js

[PRIMETSS]

I Dropped back to Webpack 1.12.9 and no longer got the error

package.json
"webpack": "1.12.9",

[DanJ210]

I have this issue as well but I'm still new to all of this so I have no idea how to drop back to Webpack.

Following the link to #21 above shows exactly what needs to be types which is great for someone like myself. Thanks!