My early 2009 17" MacBook Pro laptop randomly and VERY frequently (!!) freezes and requires a hard boot if I upgrade to ANY system over the original Leopard version it came with, including later Leopard versions or Snow Leopard 10.6.3 (just installed from a disk today). It doesn't matter what I am working on or even if I am not working on anything at all and the laptop is just sitting there doing nothing with no applications active -- I can go over to it and it's locked: mouse freeze, no access to anything. And it happens every 5-10 minutes.
I discovered this problem the first time I did an upgrade over the internet two years ago. I had to restore the original Leopard system from the disc it came with and then it stopped freezing. Then I promptly forgot about it and the warranty expired, although I have tried many times to upgrade since with no success. Now, however, I need to use Snow Leopard for obvious reasons, and I have to get this problem solved. I have seen countless blogs & discussions all over the internet about the MacBook Pro (especially 2009 models) freezing up, and the answers disappoint me.
I have repaired the hard drive using Disk Utility AND Disk Warrior (there are never repairs to be made, so that's not it) and repaired permissions many, many times to no avail. I have turned off screensavers and screen dimming features, etc., etc. Nothing has worked. There are very few things installed on this computer. Some of the same software is installed on my two other Macs (not MacBook Pro laptops) and there are no problems. I try hard avoid third party software anyhow.
This problem sure doesn't seem to be directly related with a particular system upgrade -- it's ANY system upgrade!
By the way, I just managed to download the latest firmware update in between lock-ups, and guess what? It locked up within 3 minutes.
I am trying to download the combo upgrade to see if that helps, but the dang thing keeps locking up.