Output opens within output within output

Check what you have in the Start Page and Default Topic fields. If they are the same, you'll need to change one or both of them.

Start Page should typically be index.htm and IS NOT a topic in your project. (The index.htm file is created when you generate the project and contains javascript etc that makes the rest of your topics and the skin work together.) The start page could be some other name (default, welcome, etc) but index works on webservers without requiring any customisation of the webserver. If this field is not index.htm you may need to check with your webserver admin to check the file names that have been set up to load automatically when the base url is typed in a browser window (e.g. if your site is help.mysite.com if the user types that and doesn't include any specific page, what page will the web server automatically load - and typically, index.htm is one of the usual pages)

Default Topic is the topic in your project that you want your users to see first. DO NOT name it index.htm (or whatever name you specified in Start Page (which you checked with your webserver admin 🙂  )). If your project currently includes a topic named index.htm (or the start page file), rename it to something else.

Did you create a new Preset for the output or are you trying to use an upgraded one? Have you got the right index page named and first topic in that Preset?