Hi, here is a guide, follow each step. If you’re positive you haven’t found anything after following the steps, then do what the last step says.
How to delete all bindings to a collection
Before being able to delete a collection, delete all bindings of purple elements in the Designer
– in the viewport: template page elements, and Collection Lists elements in static pages: all link settings must be turned to none
– in the Settings tab: elements can be bound to the Collection by a background image, a background color, a text color or a border color
– in the Page settings: SEO, OG and RSS can be bound to the Collection fields
– inside of every block of custom code (inside of a Collection List on static pages, or anywhere in a Template page)
– Inside of all symbols, there can be linked elements and elements with conditions. Also, symbols can be unused in pages, so check your symbols list (⇧+A)
– How to browse all elements in the Navigator to spot purple ones? In the Navigator tab, select the Body element, keep Alt pressed while you press Arrow Down as many times as needed to browse all element. This will unfold the complete tree view of your site.
– pay attention to the error message, they sometimes contain clues to where a binding is conflicting
– if you ever run into a case where you think all the bindings are deleted, but they are not, try to do a full version save of the site, by pressing cmd+shift+s on Mac or ctrl-shift-s on Windows.
It can happen that despite all your efforts, and no binding happening, you’re still unable to delete a collection. in this case, send an email to firstname.lastname@example.org (but be sure to have checked all the steps above before usign that solution)