Growl 2 works fine on some of my Macs (all recent, all running Mountain Lion), but the Growl Notification Rollup does not appear on some machines. I have carefully checked the preferences of the various copies side-by-side using screen sharing, and all have the same settings. Now I have to wonder if there are settings of which I am unaware that are external to Growl and that may affect its operation. TIA!