chaoticconfused

I figure it out. This is the proper configuration for a WordPress Sub-Domain install:

# BEGIN WordPress
<IfModule mod_rewrite.c>
# Multisite Sub-Domain

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]  # was "RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]"

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^(wp-(content|admin|includes).*) $1 [L] # was "RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]"
RewriteRule ^(.*\.php)$ $1 [L] # was "RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]"
RewriteRule . index.php [L]

# End Multisite Sub-Domain
</IfModule>

The commented out lines are for a SUB-DIRECTORY install. Those were the original ones recommended by WordPress (most likely a glitch from the migration).

Also, in any LAMP (or similar), the directive:

Header always set X-Frame-Options DENY

conflicts with WordPress functionality. If you attempt to edit themes, view the media library, and other functions of WordPress that use frames, you may get only a blank page/half functionality. The best way I could find (through probably 12 hours of research) is to use this instead:

Header always set X-Frame-Options SAMEORIGIN

It works, I can edit themes again and all that jazz.

In short, if you are using multisite wordpress:

1) Check your .htaccess configuration and ensure it is correct for the type of MU you are using (sub-directory or sub-domain).

2) Make sure you are not missing any files/have broken links in your WordPress install

3) Gatorade, it’s what plants crave.