Against my custom I applied the 10.56 update from software update on my MacBook Pro (original model!!). Came out with constant freezing. Then managed to install full update file. No help. Managed to, after a number of tries, repair permissions, no help. Then threw away apple.systempreferences.plist and all major freezes disappeared. Now I have "quick freezes" of anywhere from 1 to 10 seconds every time I command delete a file to the trash. Wait and it goes away. Tried getting rid of desktop plist also, no help. Any ideas? This is all on a new install fixing the machine up for my daughter - not much at all on there yet.