I've not used SPP for a while but I hope to get more chance to use my Merrills in the coming months. On Windows I've not updated beyond 5.5.3 and it's never been unstable - slow and annoying yes, but no crashes. Now I've got an iMac for photo editing (late 2014 but updated to Sierra); given i'm not interested in Quattro, is there any downside to installing the latest version of SPP, which i understand is reasonably stable on a mac? I have a link that enables me to download 5.5.3 to the iMac but then it seems to disappear!