# Web browsers and cache

[en français](https://wiki.unil.ch/ci/books/navigateurs-web/page/navigateurs-web-et-m%C3%A9moire-cache "Navigateurs web et mémoire cache")

#### Why clear the cache, history and cookies?

Web browsers use the following to function:

- temporary storage, known as the cache, in which they store recently viewed pages
- a browsing history, so that they can quickly reload pages viewed whilst browsing backwards
- and often cookies, when a browsing session is required, for example on websites offering a login or display filters.

Sometimes the cache, history or cookies may retain outdated information, which can lead to:

- various malfunctions
- error messages for pages that have changed address without automatic redirection
- old versions of certain pages being displayed instead of the current ones

You will then need to manually delete this outdated information to resolve the issue.

#### Here is how to do this for the most common browsers

- [Firefox](https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox)
- [Google Chrome](https://support.google.com/chrome/answer/2392709?hl=en&ref_topic=7438008&sjid=3078048358984801246-EU)
- Safari, [browsing history](https://support.apple.com/en-gb/guide/safari/sfri47acf5d6/mac) + [cookies and website data](https://support.apple.com/en-gb/guide/safari/sfri11471/16.1/mac/13.0)
- [Microsoft Edge](https://support.microsoft.com/en-gb/microsoft-edge/view-and-delete-browser-history-in-microsoft-edge-00cf7943-a9e1-975a-a33d-ac10ce454ca4)

Once you have followed the instructions above, we also recommend closing the browser and then reopening it, to maximise the chances of success.