If you are experiencing issues with Write N Cite on your Mac, you may need to upgrade to the new version of Write N Cite. The first step to doing this is deleting the existing version of Write N Cite off of your computer, this will not affect any documents that currently have citations or bibliographies created with the previous versions of Write N Cite. First, you will need to close Microsoft Word for Macs. Next select Command+Shift+G on your keyboard. In the box that pops up type ~/Library, this will allow you to temporarily access the Library directory on your Mac, this folder is typically hidden. Next, follow the path in the in image below.
Once you see the RefWorks folder, delete it and then delete everything in your Trash. Now you can navigate to the RefWorks site and download the newest version of Write N Cite. Write N Cite is located under the Tools menu and the newest version of Write N Cite for Macs should be the first available option. After you download and install Write N Cite, reopen Word and login in to Refworks.
Running Apple's Yosemite operating system will require installing Java for OS X 2014-001 which is available from Apple at http://support.apple.com/kb/DL1572. If you want a more recent version of the JDK or JRE, you can get that directly from Oracle but you will still need to install the Apple version first.
Go to https://www.dropbox.com/s/ykyo8hlndi6jbu7/PQfWInstall_4.4.1225.dmg?dl=0. Download, save, and run this installer file to add it to MS Word. (If the above link does not work you can also download the installer from the Write N Cite section of your Refworks account).
Keep in mind that after downloading the correct version of Java, you may need to completely remove Write N Cite from your computer before reinstalling it. Please see the instructions in the box above for completely removing Write N Cite from your Mac.