Purge Unused Sources
You are about to go through a process where all the sources in the Master Source List that are not currently being referenced will be removed from the list. This is a good way to remove sources that were mis-entered and later corrected.
The Purge Unused Sources screen is reached by choosing the Purge Unused option from the Options button on the Master Source List screen.
The Master Source List is reached by clicking Cite a Master Source on the right side of the Assigned Sources window. (The Assigned Sources window is displayed by clicking the Sources icon on the Information window or the Husband or Wife box on the Family View or the Pedigree View.) The Source List is also available by choosing Master Lists / Source from the View tab of the Ribbon bar.