You should see a list of Active Application Add-ins, in which there will be a number of EndNote related items. Remove EndNote Cwyw add-in and reinstall: Go to the File menu on the left of the tab bar and select Options and then the Add-Ins option on the left. However, you may have found that the Application dropdown is greyed out and can’t be changed. Once you’ve changed this, restart Word and it should work. Use this to select EndNote rather than EndNote Web. Go to the Application tab and look for the Application dropdown. Change EndNote Cite-While-You-Write (Cwyw) Settings: Go to the EndNote Web tab in Word and click the Preferences button.

The solution to your problem depends exactly how badly things have gone wrong. When clicking on this tab you get asked to login to EndNote Web, and cannot access any references you have stored in your local EndNote library. When loading Microsoft Word the EndNote tab that normally appears has been replaced with a tab labelled EndNote Web.

You have EndNote and Microsoft Word 2010 installed.

I should probably first state that I’m writing this a few days after I fixed this problem, so I may have some of the details wrong. Robin's Blog How to: Fix problem where EndNote only shows the EndNote Web toolbar in Word December 2, 2010

Endnote web down