I am not sure if this is an IIS 7.5, Security/Permissions, PHP, Windows 2008 R2 or WordPress Issue. However recently after moving from IIS6 one Windows 2003 to a new Windows 2008 R2 server I could not upload images to WordPress.
I usually use Windows Live Writer and I was getting an error like “…has failed to upload due to an error” and “Unable to create directory”.
When I went to the admin interface and tried to upload a file through the Media I would get an error about the directory “Unable to create directory … Is its parent directory writable by the server?”.
I checked and rechecked the permissions. I also made sure the entire directory was NOT read-only.
By happenstance I decided to give the group Everyone FULL ACCESS to the directory. Then I could finally upload the files.
I then removed this access and I still could upload files. It is really bad security to leave EVERYONE with FULL or even read/write access.
I’m not sure if these permissions will stick after a server restart but hopefully all is well now.