Save as a compressed library is particularly helpful if you wish to send your reference library to another person. This is because this process will generate only one file which can be easily sent via cloud drive or attached in your email. 

1. Click on File.
2. Select Compressed Library (.enlx)...
3. Select With or Without File attachments, All References in the Library, Selected Reference(s), or References in Group/Group Set, then click on Next.
4. An .enlx file is generated for backup purpose. You can also send the .enlx file to your collaborators for sharing purpose.

EndNote provides a cloud space (EndNote Web) for you to backup your reference library. However, we DO NOT suggest synchronizing more than one reference libraries from your EndNote desktop onto your EndNote Web. This is because when you synchronize more than one libraries from the desktop version onto the EndNote Web, all references from your second EndNote desktop library will be merged into your existing EndNote Web library.

You can consider backing up your reference library using a third party cloud space (e.g. Google Drive, Dropbox, etc.) by saving your library onto these cloud-based drives (Save a Copy), so that you can backup multiple reference libraries.

If you have decided to synchronize the library with EndNote Web, you can follow the steps below:

1. Click on the Synchronize icon.
2. Login your EndNote account (for EndNote Web).
3. Click on Sign Up to create a new EndNote account if you do not have one.