You’re having exactly the same experiences I did. Freezes and crashes, system atomizing itself into crazy components, “corrupted” disk that can’t be fixed because it is “okay,” etc.

Here are the steps that enabled me to get back to work:

1. Installed smcFanControl on my iMacs and MacBook Pro, and adjusted settings until the machines ran cooler. They still run hotter than they should; and the adjustments mean my fan and hard drive will wear out sooner than they otherwise might; but the machines work again, and that’s the main thing. Be patient: It may take a day before you find the fan speed sweet spot that reduces heat sufficiently to stop your Mac behaving like a PC on crack.

2. Replaced one of my backup drives. Just bought a new one. The update fried the old one. It was under warranty but if the drive burned out because of defects in Apple’s system update (not defects in the drive itself), to whom would I turn for compensation? I just wrote it off as a loss and plugged in a new drive. This enabled me to begin running backups again. (The update had prevented me from running backups.)

3. Trained myself to repair Disk Permissions after *any* change. No less a Macintosh expert than John Gruber says repairing Disk Permissions is mostly hooey. Most of the time it’s not needed, and many Apple engineers never fix permissions (except in very limited circumstances), my friend Gruber has told me. Nevertheless, since I wasted nearly two weeks trying to recover from 10.5.7, I have converted to the religion of repairing Disk Permissions after I make any change to the system, whether it be updating Photoshop, or adding a new font to the library. In combination with the temperature control, it seems to help.

My MacBook Pro (less than a year old) still turns itself off for no reason at all from time to time, but it does it maybe once a day, or once every few days, instead of every hour of every day, every time the machine is left unattended. I consider this a win. For instance, I’m now able to take the MacBook Pro onto the stage before speaking and plug it into the lecture hall’s projection system. That sounds normal, and it is normal. But immediately after installing 10.5.7, and for weeks afterward, “normal” was impossible. If I brought my MacBook Pro to the stage, it would shut itself off while I was carrying it, and it might take as long as three minutes to reboot. (That sounds like my machine was defective, but it isn’t; 10.5.7 is defective. Fortunately its worst offenses can be worked around.)

I’m looking forward to Snow Leopard—and doing an Archive and Install of Snow Leopard on all my studio’s Macs.

This really solved the Sleep problem on my MacBook, although it is a hack.
Thanks Eric for making me to have a look on the discussion once again.

I’ll just have to put up with it until apple (hopefully) fixes the problem.

I was in the process of getting my G5 2.5 Quadcore ready for sale & thankfully had backed up everything on the machine – I then started doing a clean install of Leopard on a totally clean Hard Drive from the original installer – fine everything sweet – then every time I used the software update & restarted the machine I was presented with a black screen – nothing – no access to hard drive etc. I repeatedly reinstalled the software & tried updating – initially unaware of the new 10.5.7 assuming I was just updating to 10.5.6 – each time on restart after software update Black Screen – nightmare! After 3 or 4 attempts I then took a look at the software update & realized the problem could only be coming from 10.5.7 (before my computer never missed a beat – no crashes etc solid under every previous version of 10.5) – I can only assume from the symptoms that after the update there is some incompatibility with the Video Drivers – hence the Black Screen.

Anyone who has this problem & has the grace to use another machine to read this – I suggest you :
1) hold down eject button on start up – to eject any cd/dvds in your machine
2) Insert an older operating system – such as the original 10.5 disc
3) Once the operating system disc is loaded – hold down the power button to shut down the machine
4) Press the Power Button to start the machine up & hold down the “c” key which will force the computer to start up from the operating disc you have loaded on the computer

This should get you access to the machine & the screen should be working

Then you will have options to install an older operating system to get you back up & running – make sure you pick the option you want – if you using time machine, you should be able to restore the machine to a previous state prior to the update.

I hope this helps with anyone going through ‘10.5.7 no screen problems’ – good luck!

I will gladly trade slightly less beuatiful products for ones which are actually robust & reliable.

I will even pay a premium to do so –

oh wait, I am already doing that!? :-(

FAIL.