Odds are, if you own a mac you probably don't own a Zune HD. For those that do however, a member at Zuneboads has found a way to get them to work together. The workaround involves a simple command edit using Microsoft's "Windows Phone 7 Connector". Once done the Zune HD will able to sync up with Mac OS, as shown above. Obviously this app wasn't designed with this in mind so please use at your own risk.
How to sync your Zune with a Mac