WordPress on Windows/IIS cannot upgrade, add plugins, upload themes

I have been struggling with this one ever since I moved my WordPress installation from my old Windows 2003 server to a new Windows Server 2008 machine. If I try to use “automatic upgrade” to upgrade to the latest WordPress release or upgrade or add a new plugin I get to the “Connection Information” page asking me to fill out ftp host name, user name and password. When I try to upload a new WordPress theme I get 500 Internal Server Error. I have understood that this is a permissions problem in the file system but have failed to be able to solve it.
I have been trying to give various users and groups permissions on the everything from the entire wordpress directory to the wp-content folder.

However what I did not realize until today is that (at least in my Windows installation) the group IIS_IUSRS does not have any group members but I should instead give the user IUSR permissions. Too easy… 🙂
So simply do this: give user IUSR Modify and Write permissions to your WordPress directory.



  1. Hi Friend

    I was doing the same thing for days, adding the group, just added the user on the www directory in IIS as i only have the blog over there ;

    thank you for your help.


  2. Hi, thanks for the advice, I can now install plugins etc on my IIS7 Worpress installation. I have been struggling with this problem for hours until I came accross your blog. You saved me alot of time.


  3. When trying to upgrade to 3.6 I got this message:

    Update WordPress
    Downloading update from http://wordpress.org/wordpress-3.6-new-bundled.zip…
    Download failed.: Destination directory for file streaming does not exist or is not writable.
    Installation Failed

    Solution by yylang1987:
    I checked the wp-config.php, and found no define about WP_TEMP_DIR.
    so I added
    define(‘WP_TEMP_DIR’, ABSPATH . ‘wp-content/’);

    Source: http://wordpress.org/support/topic/download-failed-destination-directory-for-file-streaming-does-not-exist-or-is-n

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