cumulate references in bibliography

Each time I add a citation in the text, the complete reference is placed into the bibliography appropriately. However, this new complete bibliography appears, in addition to the original complete bibliography which follows the new complete bibliography. In other words, each time I add a new citation, an entire revised bibliography is inserted in the reference list preceding the prior complete bibliography.  This process is repeated each time I add a new citation.  So the entire bibliography (50+ references) is repeated over and over again each time I add a new citation.  

My question: How do I add just the new reference to the existing bibliography without replicating the entire previous bibliography with each new citation added to the text?

This is usually due to corrupt citations, or you are saving to a format that is not an word format and it is erasing your word generated fields.  

What word processor and version, what endnote version and what operating system verstion?  How are saving the document (make sure .doc or .docx, if word).  

If  corrupted citations see http://endnote.com/kb/81143  (but I don’t usually need to copy the text to a new document). 

Dear Leanne,

Thank you for getting back to me so promptly.

I am using Endnote X8 and

Microsoft Word for Mac version 15.27 (161010) (2016 version)

saving to .docx format

My Mac version is OSX El Capitan Version 10.11.3

Almost all the references I am using I import directly from pubmed

What do you recommend that I try?

Barry

As I said, first make sure there are no corrupted fields in the document by following these instructions  http://endnote.com/kb/81143