Overview:
The System Administrator attempts to edit a record that is loaded through a VisualForce page, such as a Call or Survey, but no action occurs.
Chrome developers console displays the error message: Unsafe JavaScript attempt to initiate a navigation.
Root Cause:
This error occurs when a System Administrator has the option Development Mode enabled on the user record.
This is a Salesforce feature used by Developers to assist in the creation of VisualForce pages.
Solution:
Users should not be using Development Mode as it can block some types of requests sent by VisualForce pages.
Disable Development Mode on the User record.
Related Documentation:
Salesforce Documentation: Salesforce Development Mode