I have a MacBook Pro and a MacPro both running 10.6.1. My Sony PRS600 is on its way so I can't test how well it works yet, but I have installed the Sony eReaderLibrary software on both machines. On the laptop it appears to be running OK. On my MacPro I double click on the app and it starts, but although it starts, no window appears and nothing works. If I click of anything in the menu bar - ie about, edit, file, view help etc absolutely nothing happens. I have Adobe Digital Editions on both machines and that works fine. The only difference is that I installed the Adobe software BEFORE the Sony on my MacPro and AFTER on my laptop. Any suggestions?