After we listed a few of the ways you can convert .docx to .doc in the July 2010 issue of Macworld, readers suggested a few more. An anonymous MacOSXHints.com reader reminds us of an even easier way, using the built-in command line utility textutil:
If you are using Leopard or Snow Leopard, open a Terminal window, navigate to the location of the .docx file you wish to convert and enter textutil -convert doc myFile.docx (where myFile.docx is the file you need to convert). It's also possible to just drag your document in the Finder and drop it on the Terminal window to get the correct full path to it. The operation will output myFile.doc in the same folder as the original after the conversion.
While command-line junkies may like this method's flexibility, it isn't the most user-friendly option. However, one of that tip's commenters offered up a way to turn it into an Automator service, enabling you to convert files right from the Finder.
To do so, open up Automator and create a new Service that receives selected files or folders from the Finder as input. Drag Run Shell Script from the Utilities section of the Actions library into the right-hand pane. Set the rightmost drop-down to receive input As Arguments. Then, next to do in the second line of the Run Shell Script's text box, enter textutil -convert doc "$@".
Save the service with whatever name you like (Convert To .Doc, for example). Now, when you right click on a file in the Finder, you'll have a Convert To .Doc option at the bottom of the context menu; it should work with .txt, .html, .rtf, .rtfd, .doc, .docx, .wordml, .odt, and .webarchive files.
This story, "More Ways to Convert .docx Files to .doc" was originally published by Macworld.