Webpack error on yarn run build:production

Webpack Error:

Hash: 9f3e91dd416ab52900c4                                                    i Version: webpack 2.1.0-beta.26
Time: 6262ms
  [13] multi customizer 40 bytes {1} [built]
  [14] multi main 52 bytes {0} [built]
    + 13 hidden modules

ERROR in ./styles/main.scss
Module build failed: Error
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/webpack/lib/NormalModule.js:143:35
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:359:11
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:225:18
    at runSyncOrAsync (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:138:3)
    at iterateNormalLoaders (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:224:2)
    at iterateNormalLoaders (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:213:10)
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:228:3
    at context.callback (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:106:13)
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/postcss-loader/index.js:119:13

ERROR in ./styles/main.scss
Module build failed: Error
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/webpack/lib/NormalModule.js:143:35
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:359:11
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:225:18
    at runSyncOrAsync (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:138:3)
    at iterateNormalLoaders (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:224:2)
    at iterateNormalLoaders (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:213:10)
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:228:3
    at context.callback (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:106:13)
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/postcss-loader/index.js:119:13

ERROR in ./styles/main.scss
Module build failed: Error
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/webpack/lib/NormalModule.js:143:35
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:359:11
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:225:18
    at runSyncOrAsync (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:138:3)
    at iterateNormalLoaders (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:224:2)
    at iterateNormalLoaders (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:213:10)
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:228:3
    at context.callback (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/loader-runner/lib/LoaderRunner.js:106:13)
    at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/postcss-loader/index.js:119:13

ERROR in /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/extract-text-webpack-plugin/loader.js?{"omit":1,"remove":true}!/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/style-loader/index.js!/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/css-loader/index.js?-sourceMap!/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/postcss-loader/index.js!/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/resolve-url-loader/index.js?-sourceMap!/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/sass-loader/index.js?-sourceMap!/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/assets/styles/main.scss doesn't export content
Child extract-text-webpack-plugin:
        + 1 hidden modules

    ERROR in ../~/css-loader?-sourceMap!../~/postcss-loader!../~/resolve-url-loader?-sourceMap!../~/sass-loader?-sourceMap!./styles/main.scss
    Module build failed: Error: ENOENT: no such file or directory, open '/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/svgo/lib/svgo/../../.svgo.yml'
        at Object.fs.openSync (fs.js:557:18)
        at Object.fs.readFileSync (fs.js:467:33)
        at module.exports (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/svgo/lib/svgo/config.js:31:48)
        at new module.exports (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/svgo/lib/svgo.js:21:19)
        at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/postcss-svgo/dist/index.js:91:16
        at Object.creator [as postcssSvgo] (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/postcss/lib/postcss.js:150:35)
        at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/cssnano/dist/index.js:283:40
        at Array.forEach (native)
        at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/cssnano/dist/index.js:270:29
        at creator (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/postcss/lib/postcss.js:150:35)
        at processCss (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/css-loader/lib/processCss.js:186:16)
        at Object.module.exports (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/css-loader/lib/loader.js:24:2)
Child extract-text-webpack-plugin:
        + 1 hidden modules

    ERROR in ../~/css-loader?-sourceMap!../~/postcss-loader!../~/resolve-url-loader?-sourceMap!../~/sass-loader?-sourceMap!./styles/main.scss
    Module build failed: Error: ENOENT: no such file or directory, open '/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/svgo/lib/svgo/../../.svgo.yml'
        at Object.fs.openSync (fs.js:557:18)
        at Object.fs.readFileSync (fs.js:467:33)
        at module.exports (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/svgo/lib/svgo/config.js:31:48)
        at new module.exports (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/svgo/lib/svgo.js:21:19)
        at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/postcss-svgo/dist/index.js:91:16
        at Object.creator [as postcssSvgo] (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/postcss/lib/postcss.js:150:35)
        at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/cssnano/dist/index.js:283:40
        at Array.forEach (native)
        at /Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/cssnano/dist/index.js:270:29
        at creator (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/postcss/lib/postcss.js:150:35)
        at processCss (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/css-loader/lib/processCss.js:186:16)
        at Object.module.exports (/Applications/MAMP/htdocs/openminds/wp-content/themes/hoang/node_modules/css-loader/lib/loader.js:24:2)
error Command failed with exit code 2.

I found the solution to be with the .yarnclean to do with .yml files
svgo issue

Being new to Yarn at this stage, I had accidentally created the .yarnclean file. I don't need it yet so I have deleted it completely and all works.

saved my life. thanks.