You have used the References > Find Duplicates command to find duplicates in your library. EndNote searched the showing references for duplicates, and will display each set of possible duplicates.
Differences between reference fields are shown with blue highlighting. In addition, EndNote takes you to the first reference field in which there is dissimilar content between the two duplicate references. Scroll through the list to see which fields contain duplicate content and which contain dissimilar content.
Select a record and add or delete text in a field just as you would in the Reference window. Click Keep This Record to save your changes. The following commands are available from the right-click menu: Cut, Copy, Paste, Paste without Text Styles, Clear, and Select All.
Note: Do not use Skip because your changes will not be saved.
Click Keep This Record to save that particular reference and throw the other one in the Trash.
Click Skip to leave both references in the library, intact. They will appear in a temporary Duplicate References group, so you can review them later.
Click Cancel to stop the Duplicate References operation. All duplicates will appear in the temporary Duplicate References group if you wish to review them.
The older (first entered) reference will always appear in the left column.
Warning: Before selecting Keep This Record, which will delete the duplicate, check the record numbers to be sure that you are not deleting a reference already cited in a paper.
By default, references are considered duplicates if they have the same reference type (such as Journal Article or Book), and the Author, Year, and Title fields are identical. The criteria for detecting duplicates can be changed using the Duplicates settings in EndNote’s Preferences dialog.
References that appear identical may not show up as duplicates if the information in the fields EndNote checks is slightly different or if the reference types are different. When trying to determine how references differ, it is helpful to know exactly how EndNote compares them.
Author: Compares last name and first initials (even if the first or middle name are written in full). Capitalization is not important.
Year: Compared exactly as entered.
Title: Leading articles "A," "An," or "The" are ignored, but punctuation is included. Capitalization is not important.
Reference Type: Compared exactly as entered.
When there are no more sets of duplicates to compare, the Find Duplicates dialog closes. The Duplicate References group is refreshed, the Trash group contains the unwanted duplicate references, and all other groups are updated appropriately. The Duplicate References group is empty unless at least one set of duplicates was skipped or the Duplicate References operation was cancelled.