I had a web site set up on our server's system partition. The entire web directory structure was writable by IUSR and NETWORK SERVICE to allow the web app to generate caches of HTML files.
When I moved the web directory to a secondary (freshly created) partition, the web app could no longer overwrite pre-existing files (Permission Denied Error). It can create new files and overwrite them, just not the old ones.
The directory folders still have FULL rights for IUSR and NETWORK SERVICE and non of the files are marked as read-only.
Any ideas why this is?