# Developing with Yarn & Webpack, issues with error reporting and css

**URL:** https://discourse.roots.io/t/developing-with-yarn-webpack-issues-with-error-reporting-and-css/10828
**Category:** sage
**Tags:** webpack
**Created:** 2017-11-05T17:20:22Z
**Posts:** 19
**Showing post:** 10 of 19

## Post 10 by @MWDelaney — 2017-11-07T15:18:16Z

> [@slam](#):
>
> In yarn start the css is not rendered and visible.

> [@Stephen](#):
>
> I don’t really understand what you mean by this but I can only assume that you’re confused by the sourcemaps

Another possibility is that `yarn build:production` was run. If `yarn build:production` is run, you’ll need to run `yarn build` at least once before running `yarn start` again to clear out the versioned, cache-busting files and begin developing again. This catches me off guard about once every three weeks.

`yarn start` also runs its own little web server at `localhost:3000` where you’ll see the live changes to your site. Are you able to reach that address while `yarn:start` is running?

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