Create an Endnote online account and get regular backups of your Endnote library.
The account is used for synchronization between several devices and sharing of the Endnote library.
The Endnote online account is created in Endnote via the menu item:
Click "Enable Sync".
Choose "Sign up" and create an Endnote Online account.
You can share your Endnote library and all your references with others who have also created an Endnote Online account.
In Endnote, under the "File" menu click on "Share"
Complete "Invite more people".
Under "Permission", choose what rights you want to give to those you share the library with.
Accept the Share Endnote Library invitation that you receive by email. Log in with your Endnote online account.
In Endnote, in the menu under "File" select "Open Shared Library".