If you use the same search strategy to search multiple online sources, you may introduce duplicate references into your EndNote library. There are two methods to identify and remove duplicates:
You can identify and delete duplicates in your EndNote library after downloading is completed. This process allows you to view each duplicate before deleting it. See Finding Duplicate References.
You can discard duplicates during the downloading process, as described below.
To automatically discard duplicates:
Display the Duplicates panel.
From the Online Search Results panel, select the “Automatically discard duplicates” check box.
When you select the “Automatically discard duplicates” check box, EndNote automatically discards duplicate references when retrieving references from an online database. The duplicates are never inserted into the library. This setting applies when you perform a search in Integrated Library Mode or Online Search Mode.
If you are using Integrated Library & Online Search Mode when performing an online database search, it applies to the permanent All References library.
If you are using Online Search Mode when performing an online database search, it applies to the temporary Online References library.
Note: These settings do not apply to the "Merge Duplicates in Bibliography" setting defined in Formatting Preferences. The duplicates are never inserted into the bibliography.