I was blitzed, too. Down to 256 from 512. I've switched the DIMMs in my TiBook: Problem gone. But it's still a drag. Some people might not even NOTICE that they've lost some RAM in the process of updating. I got plenty of mail on macnews.net.tc about the problem, so I guess this problem is more widely spread that this thread shows... Shouldn't happen, really shouldn't happen. Wonder whether a zap-PRAM would have helped, too.