1. If you're finding that the references in Mendeley Reference Manager aren't matching up with the references in Mendeley Web, click on the Sync button in the upper right hand corner of the desktop application.

2. After the sync happens and the green spinny wheel disappears, your Mendeley Desktop library will be synced to your Mendeley web library.  Go to the Mendeley website, sign in, and click on Library. Your web library will now contain the same references that are in your desktop library.