Hi @fededim
That’s odd - I’ve never had to do that on IIS to get Umbraco working…
The umbraco folder in your content root is for the Umbraco logs and temp data - none of which should be publically accessible. The wwwroot/umbraco folder is the public assets for the backoffice. This is normal and should have worked for you without needing to add that section to the web.config.
I can only think that your IIS has something configured that is interfering with normal requests?
Justin