EndNote libraries should never be stored in cloud-syncing folders such as Dropbox, iCloud, OneDrive, Box, SugarSync, etc. Syncing folders corrupt EndNote libraries over time. Save your library to the local device and then sync or create a backup file to share/store on a cloud drive. For macOS users, make sure the folder your library is not being "optimized".
Keep the EndNote library file together with the .Data folder
EndNote libraries are made up of two parts: the .enl file and the .Data folder. These two parts must be kept together; both are needed for the library to work correctly. If you received an empty library from someone else, ask them to send you the compressed/archive version of their library instead.
Cite While You Write in Microsoft Word
Make edits to citations in EndNote
If you notice an error in your citation in your Word document, use the EndNote toolbar or go to the citation in EndNote to make any edits. Changes made directly into the Word text will eventually be overwritten.
Create a clean copy of your document for submission
Instructors and journal editors may ask you to submit a copy of your work that does not include the embedded EndNote field codes. To do this, use the EndNote toolbar in Microsoft Word to convert your document to plain text. This will generate a copy of the work that you can save and send to others without any of the embedded EndNote links to your library.