Duplicated pdf in "Downloaded" file..

Hi, I have an issue with the file location where the pdf's are stored. I followed Mendeley's recommendation and imported my previous EndNote references (XML format) into Mendeley. All the pdf attached to the EN references are in a file. After importing those ref, I found a file in Mendeley Desktop called "Downloaded" with all the same pdfs and each one was duplicated... How shall I remove keep only 1 version of each pdf (instead of 3 now). Remove all references and point out the EN file? How shall I prevent Mendeley from downloading unwanted pdf's? Thank you for your help. Regards, Ervan