Got this email from Parallels today telling me that if I go with 10.9 my Parallels software will not work anymore. so it looks like 10.9 is not truly free. If I want to run Windows and I.E., I will have to invest about $40 for the new version of Parallels. This is why I did not move from 10.8 to 10.9 yet...I just knew this kind of thing was going to happen + Samsung support told me on the phone that there was NO driver to support 10.9 to make my laser printer work and print.