Once you have created an EndNote Online account, you can create a backup of your desktop library by syncing it with your EndNote Online library.
To enable Sync, visit the Preferences menu.
PC - Select Edit then Preferences
Mac - Select EndNote X9 then Preferences
Choose Sync from the menu
Click Enable Sync
Enter your EndNote Online credentials then click OK
Check the Sync Automatically if you would like to have your library sync automatically when you open and close EndNote. We recommend using this features
PC - Click OK
Mac - Click Save