Click the link below to open up chapter 12 of the book. This chapter covers the steps you should perform to close out the year in CYD.
This happens with some installations of Outlook. You can fix it by using a different symbol, try the # sign instead. You will have to change the search criteria for each of your context folders to look for the #context (#NA, #WF, etc..) instead of the @sign (@NA, @WF, etc..)
CYD is only supported on Windows today, I am planning to test it on Outlook for Mac, sometime this year (2015)
You can find step by step instructions on how to add the Query Builder tab in Outlook.