First, open a blank, new document in Word, and try to insert a single citation into this new document using the EndNote tools. To do this, highlight the reference you would like to insert in your EndNote library, then switch to the Word document and go to "Tools > EndNote > Insert Selected Citation". Once the citation has been inserted, go to "Tools > EndNote > Format Bibliography" and choose the "Author/Date" output style. If this works properly, click here. If this does not work properly, click here.
Problems with Word in General:
First, make sure you have the latest updates for Microsoft Word.
Also, make sure you have the latest updates for your version of EndNote, available here.
Do the tools show up in Word? If not, click here.
Do you get an error message that says "The macro could not be found or has been disabled"? If so, click here.
Do you get an error message that says "This Command is Not Available Because a Document Window is Not Active"? If so, click here.
Do you get an error message that says "Service Error: Generic"? If so, click here.
Are you seeing the entire reference information in the document, or strange codes, such as "{ADDIN EN.CITE …}"? If so, click here.
Do you get an error message that says "An attempt was made to access an unnamed file past its end"? If so, click here.
When you click on the tools in Word, does nothing happen at all? If so, click here.
Do you get an error message that says "Invalid Class String"? If so, click here.
Do you get an error message with EndNote 6 that says "Unknown Error", refers to memory, or "0X800A1007"? If so, click here
Do you get an error message that says "Server Threw an Exception" or "Unhandled Exception"? If so, click here
 
Problems with a Specific Word Document:
Are you seeing the abstract in your bibliography and you don't want it to be present? If so, click here.
Are your citations not showing up in the document after you insert them, but the reference list is generated below? If so, click here.
Do you get a dialog box that says "EndNote Select Matching Reference"? If so, click here.
Do you get an error message that says "Service Error: Generic"? If so, click here.
Have you made changes to the references in your library, but those changes aren't reflected in your document? If so, click here.
Are you trying to type changes directly into the citations or the bibliography, but the changes are overwritten by the EndNote program? If so, click here.
Are you trying to add page numbers to your citations? If so, click here.
Are your numbered citations not starting with number 1, even though you're using a style that sorts the citations in the order of appearance? If so, click here.
Have your citations shifted up one position in the document? If so, click here.
Have you used Word's Track Changes, or have you pasted in text from another document with Track Changes enabled? Or are you getting a message: "The requested object could not be found"? If so, click here.
The problem may be due to corrupt code in the document. If the cursor jumps to another portion of the document when inserting citations or formatting the bibliography, this is also a sign of bad code. Click here for instructions on how to clean up this code.
Is there any chance you're inserting a large group of citations (20 or more) all in the same place? If so, click here.