March 20th, 2009
Installing WordPress MU in subdirectory of existing WordPress blog
If only for my own sanity should I ever want to do this again, here are some useful tips for installing WordPress MU into a subdirectory on a webserver that already has a normal version of WordPress installed in the root. If that makes no sense to you then don’t worry, you probably don’t need to know:
- Download ZIP file and unzip files into the subdirectory (eg “/mu/”)
- Open “/mu/wp-blog-header.php”
- Locate line 9:
if ( !file_exists( dirname(__FILE__) . '/wp-config.php')
&& !file_exists( dirname( dirname(__FILE__) ) . '/wp-config.php')) { - Edit this line to be:
if ( !file_exists( dirname(__FILE__) . '/wp-config.php') ) { - Continue normal installation by going to “/mu/index.php”
The reason for this? If the MU installer detects the wp-config.php file in the root directory it thinks it’s already installed, but it isn’t. What it’s finding is the wp-config.php for the existing single-user version of WordPress.
There you go.

