This feature helps to cut down on the creation of duplicate Tasks by showing the user their own existing Tasks for an Account record set (includes all related Opportunities, Cases, Contacts etc) before they create a new Task.
When a new Task is created and the user has uncompleted existing Task(s) for the Account record, options are presented to change the Due Date, Edit or Complete the Task(s), or create a new Task.
Configuring
The default Setting Value is True. When creating a new Task, options to edit any existing Tasks for the current user for the related Account will appear.
To disable this feature, use a Setting Value of False.
Setting Name: TasksNewPromptToEditExisting
Setting Value: True / False
If the Setting doesn’t exist but the “Existing Task” box is presented and the feature is required then no change needs to take place.
Click “Save,” then Reset the Application Cache: