If you have a new Article that you want to have accessible from a browser using a URL, but do not want it to appear under as a Menu item, you may get a 404 error.
The workaround we use so that you can access the article but not visibly have to see it under any menu, is to go to the Menu Manager and add a new menu for the purpose of 'holding' this article, and any others you wish to give the same treatment.
Now go to the Module Manager and select this 'new menu'. Under the Menu Assignment section, set the Menu to None. Also make sure the Menu remains 'enabled'.
Now go back to the Menu Manager and add your article to that Menu. Hopefully you should now be able to access your Article without seeing it shown under a menu, and without seeing a 404 error
We hope this steers you in the right direction, however, if anyone has a more elegant solution to this problem, we will of course be delighted to hear from you.