Write-N-Cite is compatible with Word for Mac. Are you sure you are downloading the Mac version of Write-N-Cite? When you are logged into Refworks, click on TOOLS, then WRITE-N-CITE. When the page loads, it will default to the Windows version. At the top of the page you will see a link to the Mac version. You can find more instructions here: http://www.refworks.com/refworks2/help/Refworks2.htm#Installing_Write-N-Cite_for_Mac.htm Also, make sure that all Word windows are closed before you try to download and install the software.