I'm happy for those who have had no trouble with the Parallels update. Perhaps they already had Application Sharing turned off. In any event, along with many others posting here and on the Parallels Support Forum, after updating to build 4560 and installing the Parallels Tools update, Parallels would crash every time I launched Windows XP subsequent to the tools update. Some enterprising users discovered that if you turn off Application Sharing (in Edit>Virtual Machine) the crashes disappear. This proved to be the case for me. Since I have no need to share applications between Windows and my Mac, this is a painless work-around. It's worth noting that this solution was found by users, not by Parallels tech support, who have not, as of now, responded to the issue on the forums.