Android File Transfer (AFT) quit working after I updated to Maverick on my iMac. I uninstalled the old version of AFT and downloaded a new version. AFT still didn't work. I moved AFT from the Applications folder to the desktop, and AFT worked fine. I then moved it into my user folder, and again it worked fine. So, moving AFT out of the Application folder to another location on the computer resolved the issue for me. I'll note I did not and do not have Samsung Kies installed on my iMac or phone. It may not be necessary to uninstall AFT and then download it again. You might try simply moving AFT out of the Applications folder to another location on your computer first before uninstalling AFT and downloading a new version to see if that resolves the issue for you.