Backing up your Library
The file extension .enl stands for EndNote Library. A library is just a file on your computer, like any other file. It can be copied, renamed, deleted, moved to another folder or compressed.
It is very important to make back-up copies of your library regularly and store them on another drive. An easy way to back-up your library is to go to the File option on the menu bar, and select Compressed Library.
Make sure that the option 'With File Attachments' is selected (see below), and save to an external drive.
When EndNote creates the library, it will also create a .DATA folder which contains various files connected with the library. When you compress the library, EndNote will include the .DATA folder.
A compressed library can be uncompressed by using the File>Open command.