I have had problems using Dropbox and Endnote at the same time. Specifically, I have found that if Dropbox is open and active, it gets messed up by what appears to me to be Endnote’s behind-the-scenes activity of constantly saving little files everytime you do anything. Well, my amateur diagnosis doesn’t matter - but my solution to the problem does worK: if I pause Dropbox’s syncing function, everything works fine with Endnote. Then when I’m done with Endnote, I shut it down and un-pause Dropbox. It syncs fine then and causes no problems, and when I open a different computer (say, at home) and sync everything with Dropbox, pause it, and then open Endnote, everything looks exactly as I left it at work. The key, in short: always pause Dropbox right before you open Endnote, and only unpause it after you close Endnote.