Syncing makes the references in your EndNote Desktop and EndNote Online libraries exactly the same.
Having the same EndNote libraries allows you to use your EndNote library anywhere on any device. For example, you could use your EndNote Online library on any device while out in the field conducting a study, experiment or doing practical work. Then, once you get back to your office or study space, you could use your EndNote Desktop library on your computer/laptop for more functionality.
Please see the Sync and share page of the EndNote Desktop guide for more details.
Video: EndNote Sync: EndNote X7.1 or Later [2:31] by EndNote Training.
It is not necessary to enter e-mail addresses and password each time you synchronize your references between your EndNote Desktop and EndNote Online libraries.
EndNote automatically begins the Sync process every 15 minutes (background processing) if you have selected the Sync Automatically check box in your sync preferences within EndNote Desktop.
Note: To access your sync preferences, go to your EndNote Desktop library, then go to: Edit > Preferences > Sync.
EndNote X7.1 (or later) can synchronize an unlimited number of references and 5,000 groups between your EndNote Online and EndNote Desktop library.
References can also be synchronized to a second computer and/or an EndNote library on an iPad.
For the first synchronization on any device, there are several important considerations: