Php – Localhost physical path

You need to stop one of them, or set the other to listen to a different port.

How to set the port for IIS Services

There are 2 user accounts that may come into play. One is the app pool identity set on the app pool, and the other is the anonymous user account set on the website (I assume that you're using anonymous).

First off, on the website Authentication / Anonymous settings, set that to use the app pool identity. Then you only have 1 user to worry about.

For the app pool, you can set a custom user, or use IIS APPPOOL{app pool name}. That's the user that needs write permissions on disk. Also make sure that the PHP app isn't writing to a different folder than you expect ... one that doesn't have permissions.

For why PHP doesn't work under another site, do you get any error or status code? It may be the binding isn't correct.

Some great tools to help are: - process monitor from sysinternals.com. Pretty easy to learn and it's a quick download and free. Run it while you reproduce the issue. Then stop it so that it doesn't overwhelm you with data. Search for the word 'denied'. That should jump right to where your issue is. (use this for both the first site and second site issues) - IIS logs will tell what status code you get for the second issue issue. - Failed Request Tracing (FRT) can be set at the site level, and it will also tell you a lot. This will be more helpful on the second site issue.