can not print double sided in microsoft word on mac or windows

For all of you frustrated people who have not found an answer to the problem of not being able to print double sided in word, here is the most likely solution. As one person said, they were able to print double sided pdf documents but not microsoft word documents. Well, that was my case too. Solution: On mac, open your word document. Click "file" and then click "page setup." In "page setup" click "paper size". Change the paper size to correspond to what you actually have in your printer tray. This should solve the problem. I was able to immediately print double sided. Strangely, after that, word will ask if you want to "save changes". Seems like word is trying to set your paper size for you. Anyway, in Windows, open your doc. and click "file", then click "print". When the print screen opens, go down to paper size and change to what you actually have in the printer tray. Again, success! Hope this helps.