Mu-plugins, also known as ‘must use’ plugins, are the plugins located in the “mu-plugins” folder. These are activated by default, affecting all sites on a WordPress Multisite installation.
- Almost all WPMU DEV plugins are now designed to be installed in the /wp-content/plugins/ folder on your site. Multi-domains plugin is one of the few that needs to be installed in the /wp-content/mu-plugins/ folder
- Always read carefully all Plugin Usage instructions because some plugins involve uploading PHP files and folders to a range of different locations.
Setting up your mu-plugins folder
Before you can install mu-plugins on your WordPress Multisite installation you need to create a mu-plugins folder as follows
1. Create your mu-plugins folder in wp-content using FileZilla by clicking on right clicking and selecting Create directory (refer to these instructions if you are new to FTP).
2. Add the directory name mu-plugins and click OK.
3. Right click on your mu-plugins directory and select file permissions.
4. Set the file permission to 755 and click OK.
1. Download the plugin
2. Unzip the file to extract all files into a folder on your hard drive
3. Read all installation instructions for the plugin carefully – some plugins involve uploading PHP files and folders to a range of different locations.
- Make sure you read these instructions carefully
- Many mu-plugins require additional steps to install other than those explained below
- If you don’t follow these instructions correctly the plugin won’t work and may cause problems on your installation
- WPMU DEV plugins don’t include readme or install files. You need to refer to the install page where you downloaded the plugin
4. Launch FileZilla (refer to these instructions if you are new to FTP).
5. Open up your mu-plugins folder for your WordPress Directory (located within wp-content folder of your public_html folder)
6. Select the PHP file(s) that you need to install from inside the mu-plugin folder on your computer and drag it into your wp-content/mu-plugin folder in your WordPress Directory.
- Remember to read all installation steps for your plugin and follow them closely as many mu-plugins require additional steps to install.
7. Once you have completed all of these steps correctly the mu-plugin should automatically be activated on your site.