The advantage of using the Import command to combine libraries is its ability to filter out duplicate references during the import operation.
Note: Before merging libraries, it is a good idea to make a backup copy of the library into which you are transferring references.
To import an EndNote library into an EndNote library:
(Optional) If you want to import only a subset of references from a library, first open that library and show only the references you wish to copy. For example, if the library says, "Showing 10 out of 200 references," EndNote imports only 10 references. If the library you are importing is locked or in "Read-Only" mode, all references are imported regardless of what is currently showing.
Open the library into which you want to import the references.
From the File menu, select Import.
Click the Choose File button Use the top half of the dialog to locate and open the library you want to import. Select the file and click OK.
From the Import Options list, select EndNote Library.
Select an option from the Duplicates list:
Import All: Imports the references, including duplicates.
Discard Duplicates: Imports the references, except duplicates.
Import into Duplicates Library: Duplicate references are imported into a library called File-Dupl.enl, where "File" is the name of the library into which you are importing.
By default, a reference is considered a duplicate when the Author, Year, Title, and Reference Type match a reference already in the library. See Duplicates Preferences if you would like to change the duplicates criteria.
Set the Text Translation option to No Translation. Extended characters, saved as Unicode in EndNote, will transfer correctly.
Click Import to import the file.
Note: The time required to import an EndNote library is proportionate to the size of the library. Refer to the progress indicator to determine when EndNote has completed the task.
When the import is complete, only newly imported references display in the Library window. This is the time to add a keyword to each imported reference with the Change Field command or to peruse the imported data to make sure it imported as expected. Make sure to check references that contain extended characters.
To return all of your references to the library display (including the newly imported ones), select Show All References from the References menu.