When you create your EndNote library, one option is to make a Package Library.
What is it? Each EndNote library is made up of a filename.ENL file and an associated .DATA folder. If you want to back up, move or share a library, you must remember to copy both files. To make this easy, Macs allow packaging the files in a folder that looks like a single file.

To create an EndNote Library Package:
1. From the File menu, select either New to create a new library or Save a Copy to create a copy of the currently open library.
2. Name the file and choose where to save it.
3. Select the Save as Package option.
4. Click Save and EndNote creates a packaged version of the library.