> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://copilhost.crisp.help/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# What is a Must-Use (MU) Plugin?

A **Must-Use (MU) plugin** is a specialized WordPress plugin that is considered essential for your site’s operation.
These plugins are located in a specific sub-tab within your WordPress admin:

![](https://storage.crisp.chat/users/helpdesk/website/-/3/6/e/3/36e3df9f20e66800/image_1ro9hrn.png)

Must-Use plugins are often installed by security services or your hosting provider.
Unlike regular plugins, **they cannot be deleted or deactivated** directly from the WordPress dashboard. 

Generally, you should not modify these files unless you are an advanced user.

#### The Copilhost MU Plugin

At Copilhost, we provide a dedicated MU plugin that is vital for the proper functioning of your hosting environment. 
**You should never delete this plugin.**

It handles the automatic purging of the following caches:
* **Cloudflare**
* **WordPress Object Cache** (wp_cache_flush)
* **OPcache**

#### How does the auto-purge work?

Our plugin monitors specific WordPress **hooks** to trigger a cache clear only when necessary:
* **Cloudflare cache:** Purged during theme changes/edits, post or attachment deletions, status changes (posts/comments), new comments, or Autoptimize purges.
* **WordPress & OPcache:** Purged during menu updates, term edits, or term deletions.

The goal is simple: to leverage advanced caching technologies to boost your site's speed while ensuring your visitors always see the most up-to-date content.
In short, whenever you modify a page, we clear the appropriate caches for you.

#### What if I accidentally deleted the Copilhost MU plugin?

Don't worry, you can reinstall it in seconds:
1. Navigate to the **"Advanced"** tab of your site in the Copilhost panel.
2. Scroll down to find the **"Reinstall Copilhost Plugin"** button.

![](https://storage.crisp.chat/users/helpdesk/website/-/3/6/e/3/36e3df9f20e66800/capture-decran-2026-04-21-1358_aoh1hc.png)

If you are unsure whether the plugin is correctly installed, you can click this button at any time.
**It is a safe action and will not break your website.**