How can I lock a column (in a list) from further changes after it is initially populated? I want to lock down the "initial due date" and only allow changes to a "revised due date" column so we can track aging. Is there a way for this to be done automatically ... without manual intervention?
I don't know what you mean by automatically, I think it is not possible out of the box. But, should be possible with little customisation: You can disable quick edit on the list and write a jquery to make the field as non editable and add it to a script editor in Edit form of the list. Check this: http://www.c-sharpcorner.com/code/816/make-a-sharepoint-list-form-field-read-only-with-jquery.aspx
