# MIME type ('text/html') not a supported stylesheet MIME type

**URL:** https://discourse.roots.io/t/mime-type-text-html-not-a-supported-stylesheet-mime-type/11636
**Category:** trellis
**Created:** 2018-02-16T19:46:03Z
**Posts:** 39
**Showing post:** 13 of 39

## Post 13 by @MWDelaney — 2018-03-06T15:44:02Z

Okay, first and most importantly:

### Error messages about `main.css` while running `yarn start` (or `yarn run start`) are normal, expected, and by design.

This happens because `main.css` actually doesn’t exist while running `yarn start`. Instead, styles are built in memory and injected into the page by Webpack. Errors related to `main.css` in the browser console can and should be safely ignored while running `yarn start`.

### If you are running `yarn start` and your page/site looks unstyled in the browser

This can happen sometimes. It’s inconsistent and seems to have something to do with the imperfect software that “shares” your local theme development directory with the Vagrant box. You can fix it either by making a change to, and saving, any `.scss` file, or hard-refreshing the page (with SHIFT+Refresh), or sometimes both.

### If the missing `main.css` file message persists after running `yarn build` or `yarn build:production`

Make sure you’re not refreshing your page WHILE the `yarn` task is running. Sage versions its assets and browsers are really reluctant to give up on caches of stylesheets. Let `yarn` finish its task, wait a beat, and then refresh your browser.

Let us know if any of that helps.

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