Back up your EndNote library before creating an EndNote Online account and or sync your desktop library with EndNote Online.
In the EndNote program, Click the Sync button. If it is the first time the library has been synced on that computer, you may be prompted to create a compressed library as a backup.
If you do not have an EndNote online account, you can create one by clicking the Sign Up button. Click the OK button to start the sync. The time required to sync your desktop library the first time will depend on the number of records in the library, number and size of attached PDFs and the speed of your Internet connection.
Once you have set up your account, you can access EndNote Online from https://www.myendnoteweb.com using any computer with an Internet connection, for 2 years from the date of registration. Sign In using the email address and password which you chose when you registered.