Every so often we get a request to remove the Site Contents link from the Quick Launch of our customers’ SharePoint 2013 sites. When such a request is received, the innate response is to navigate to the Site Settings page, click Navigation (in the Look and Feel area), and then delete Site Contents from the Current Navigation heading. In certain instances, however, the Site Contents item does not appear within this heading, even though the link still shows up in the Quick Launch.
In cases where the Site Contents link displays despite it not appearing in the site navigation settings, go to your master page and check the ContentPlaceHolder element with “PlaceHolderQuickLaunchBottom” set as the id value. In a default SharePoint 2013 site (at least for SharePoint Online), you would likely look for this element in the “seattle” master page (seattle.html). Once you comment out or remove the div that is nested within the aforementioned ContentPlaceHolder element, the Site Contents link will get removed from your Quick Launch.
Many thanks to Pratikkumar Shah for identifying the workaround in this TechNet thread.