To use eCC Desktop / Shiplark on a MAC, you need to install Parallels and Windows inside it. Remember, for eCC desktop inside parallels, you will also need to use the Windows version of QuickBooks.
Alternatively you may want to use eCC Cloud through your browser, or look at one of our hosted partners like Right Networks or NovelASPect. Hosted partners can also be accessible through browsers on Mac's.
Last but not the least, parallels is not a compulsion either. You can install any virtual machine or virtual box that emulates the Windows environment and then use eCC Desktop / Shiplark.