Umbraco 4.9.x
Unpublish content via Umbraco admin.
Visit nodes on front-end of website.
404 page displayed as expected.
However after a while, the pages reppear on the website.
Log back in to Umbraco, content nodes are still unpublished.
Republish entire site, (content right click 'republish entire site')
Nodes now unpublished.
Then again after a unspecified period of time, the nodes reappear on the front end!
Your permissions are not correctly set.
Application requires Read/Write permissions on the /App_Data Folder.
When a 'Republish Entire Site' is run, Umbraco recreates the on-disk XML cache and updates the in-memory cache. If the application restarts / recycles, the in-memory cache is rebuilt from the /App_Data/umbraco.config file, which is out-dated, because it cannot be written too.
You can check this by looking at the last modified stamp on the file, it should match your last 'Republish Entire Site' event.
Microsoft - Usernames & Permissions for IIS
NetworkService = Network Service
ApplicationPoolIdentity = IIS AppPool\{app pool name}
