WordPress has an awesome feature where it can automatically upgrade itself, install themes and plugins, etc. It works fantastically on all apache and lamp installations I’ve played with, but never on Windows with IIS.
I recently upgraded to IIS7 and it was still giving me errors when trying to upgrade, install plugins, etc.
I realized that it just didn’t have write access to the file system so it couldn’t download the new files. To fix this, I added the user IIS_WPG to my wp-content directory with write permissions and immediately it worked. The full step by step went:
1. In file explorer, right click on the wp-content directory. Select Properties.
2. Select the Security Tab.
3. Click Edit.
4. Click Add
5. Type IIS_WPG, click Check Names. It should format it.
6. Uncheck Execute, check, Write and Read.
7. Click Apply.
It should work now.