One of the things that changes in WP 3.0 with multi-site is where file uploads and attachments get stored. This can be confusing to people trying to do export/imports and combine sites together.

In the .htaccess file of a multisite installation, you’ll find this little bit of code:

# uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]

The effect of this code is to redirect requests that have “files” in the name to the ms-files.php. As you may have guessed, ms-files.php is the multi-site file handler.

Files in multi-site mode are stored in the /wp-content/blogs.dir structure. Inside that directory, you will find subdirectories labeled with numbers (1, 2, 3, etc.).  Each number corresponds to the ID number of the individual site in the multi-site installation. Each one of these directories holds all the uploaded files for that installation. The ms-files.php file handles a bunch of caching parameters and then sends the file off to the browser upon request.

So the resulting URLs always look like and so forth. The “files” name is therefore special and reserved and cannot be used as a post slug and such.

When you export a site from somewhere and then import it into your new multi-site system, if you also choose to import the attachments, then you’ll have a minor problem. The attachments will be imported into this new files structure. However, the links from an older system are still referring to the old /wp-content/uploads/ directory structure that non-multi-site installs use. Therefore, you will need to go back through your posts and fix all these links and references to the attachments. I use the Search Regex plugin for this purpose, it works well enough and has some powerful search and replace capabilities.



  1. Wouldn’t something along the lines of this work?

    RewriteRule ^/wp-content/uploads/(.+) http://%{HTTP_HOST}/files/$1 [L]

  2. […] View the original article here Esta entrada fue publicada en Sin categoría y etiquetada Attachment, Handling, Multisite, WordPress. Guarda el enlace permanente. ← ¡Hola mundo! […]

  3. Looks like adding this line above the default rule works:

    RewriteRule ^wp-content/uploads/(.+) http://%{HTTP_HOST}/wp-includes/ms-files.php?file=$1 [L]

    Thanks for the post!

  4. I am using a multisite.

    When I use attachments (specifically eg attachments plugin) with multisite broadcast plugin, I get this. Do you know how to fix this?
    Warning: copy() [function.copy]: The first argument to copy() function cannot be a directory in /var/www/MYDATABASENAME/data/www/ on line 1824


    Warning: Cannot modify header information – headers already sent by (output started at /var/www/MYDATABASENAME/data/www/ in /var/www/MYDATABASENAME/data/www/ on line 866

Leave a Reply

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

Need to post PHP code? Wrap it in [php] and [/php] tags.