WordPress MU to Multisite HTACCESS

I would like to add something to my earlier article How to enable WordPress Multisite 3.0. If you are upgrading from WordPress MU (WPMU) to WordPress 3.0.x Multisite make sure to check your HTACCESS file. There have been many reports of broken images on Multisite installations after upgrading from WordPress MU. If you notice any broken images on your Multisite subdomains after upgrading, make sure to check your HTACCESS.

I tried the following HTACCESS and it fixed all these problems with broken or missing images:

#Wordpress Multi site
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
# uploaded files
RewriteRule ^files/(.+) wp-includes/ms-files.php?file=$1 [L]
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule . index.php [L]
#END WordPress Multi Site

If you are using The Donncha Domain mapping plugin to allow users to use domain names, make sure to update to the latest version that is compatible with WordPress 3.0.x. Otherwise you could see this message when a blog user tries to login:

“You don’t have permission to view this site. Please contact the system administrator.”

To update to the latest version of Donncha’s domain mapping plugin:

WordPress 3.0 Domain Mapping 0.5.2

If you notice any other issues after updating to WordPress Multisite, let me know and I will see if there is any fix.