I am new to endnote, and am having a bit of trouble finding documentation for Endnote X8 even on the endnote website…
The getting started for X7 suggested imported my existing collection, so I added ~1300 pdfs to endnote. Is it possible to “attach” a reference to an existing pdf? I am able to import a reference, then attach a pdf to that reference - but I can’t seem to figure out the opposite mechanism. Thank you for any input.
PDF files can be imported into Endnote, generate a corresponding reference record, and attach the PDF file to the record providing the PDF has a Digital Object Identifier (DOI) which can be cross-referenced with the “cross ref” database (in order to obtain the information needed to generate Endnote record). Complete Endnote records (with complete data fields) will not be generated for PDF files that do not have DOIs.
If the Endnote reference was created first you need to manually attach the PDF file to the record. Or you could try generating a duplicate Endnote record by importing the PDF file then use Endnote’s “Find Duplicates” feature to locate and compare the two records and update the one you wish to keep – but this seems more time-consuming. Just an opinion but it seems to me the best is to: 1) import the PDFs and see which records Endnote is able to fully populate; then 2) manually attach the PDFS to pre-existing reference records.
For information on importing PDF files refer to: 1) the Help option on the Endnote toolbar (search for “PDF files"); 2) the Endnote training video “PDF Auto Import Folder” located on the Endnote YouTube channel; and 3) the complete Endnote manual in PDF format which is located with the Endnote program files.
I’ve just purchased X8 and was wondering if the process for importing/merging pdfs with references has improved at all?
I have a lot of references and (unconnected) pdfs - it would be great if X8 could do some magic for me and combine them. 
Regards
Ian