Error #40007005: Form title 'X' is to similar to existing form 'Y'

The Problem
Form title 'X' is to similar to existing form 'Y'

Form titles must be sufficiently unique to distinguish them from each other in saved data.

Solutions
  1. Change the title of your form so that it doesn't conflict with an existing form. This permanently resolves the conflict, and the title can thereafter be changed.
  2. Save the form
  3. Edit the form and change the title to whatever you wish.