EndNote allows you to import citation files from external databases. However, some of these files (e.g. nbib, RIS) are simple plain-text files and, as such, macOS may not recognize them automatically as files that you want to open with EndNote to import their references. To learn how to set up your macOS computer to automatically open such external citation files with EndNote as a way to import references, follow the example below:
Say we would like to import these PubMed search results as references. Click on the “Send to” menu:
Select “Citation manager” and “Create File”. PubMed will export an nbib file to your computer. Select that file in the Finder and use the “Get Info” command/menu item:
In the Info window that comes up for the file, select the “Open with:” menu and select the EndNote app (make sure to select the EndNote app and not just the enclosing EndNote folder:
Also make sure to check the “Always Open With” option. Finally, click the “Change All” button in the Info window so macOS knows to automatically open every future nbib file the same way.
Once you’ve done this, double-clicking nbib files will prompt macOS to open them with EndNote (you may be prompted to select your EndNote library) and import the contents as references.