Server Error in '/Some' Application.
Access to the path '(...)\App_Data\Sitefinity\Configuration\ToolboxesConfig.config' is denied.
and it still happens in v. 9! but they won't post the fixes publically for us to find.
Even if you give Network_Service full control, propagate to all children
and make all files in the project folder writeable.
You'll still get Access to the path 'D:\...\...\..._2016_dev\App_Data\Sitefinity\Configuration\SearchConfig.config' is denied.
I'm stuck on the initial deploy of a new project
The only way to get an SF running on a windows server is to also add to the Project folder security and all children:
EVERYONE and ISUR and grant them FULL control.
With such a non-secure requirement, no wonder they don't publish it publicly. Hope this helps the next person.