Not sure if this is absolutely random, however I had successfully installed Leopard overnight. This morning when returning to my upgraded macbook I was greeted with a screen notifying me that there was a software update available and requested permission to reboot. In Brief. - Macbook 1.83 Core2 system - 2gb memory - 120gb internal drive (over 30gb free space) - External 120gb Lacie attached - connected over wireless to cable modem 1. Installed (upgrade from tiger) leapord 2. Approved request to install updates 3. System either started updates, or hung (screen went to desktop background with no dock or toolbar) 4. came back 30 minutes later to system only showing my desktop background with no dock or toolbar. 5. let sit for an other 30 minutes and also noted that cable modem was down. 6. got back on internet (rebooted cable modem, and confirmed with my G4 system) 7. no change on macbook so rebooted. 8. System booted into setup assistant, when completed setup assistant it would restart with no way of exiting. 9. Rebooted and went into setup assistant again. 10. Booted into Target Disk mode and verified that all my files were still in tact ( I had a backup of them anyway but wanted to confrim) 11. Now formatting and installing Leapord fresh 12. So far NOT impressed with this experience. The long version Since I like to have the updates when they came out I accepted Leopard's request to install them. Immediatly after this accepting and entering my password, my screen changed to show my desktop background (no dock, no toolbar) and sat. I figured the normal Software update window would pop up so I continued on to my normal morning routine to finish this later. 30 minutes later, the system was still in this position so I let it sit again while I continued to clean. About 30 minutes later I noticed that my cable modem was also offline (lost connection with ISP) and that my system was STILL hung only showing my desktop background (caps lock light toggled, and my mouse still worked though). I have no idea if the system was downloading or not, but I did not hear any hardrive activity nor did I see any wireless activity on my wireless router. I rebooted my cable modem and let it sit for an additional 30 minutes with no change on my macbook. After that last 30 minute window, I rebooted my macbook and was greeted by the Setup Assistant window. I (reluctantly) entered my information and completed the process, only to have Setup Assistant restart again. I rebooted and again came to Setup Assistant. I then grabbed my firewire cable and put the MacBook into Target Disk mode to confirm that my files and OS was still there, and that my entire system wasn't wiped. Yep, everything was still there (though I had a .dmg backup I made prior to the upgrade), it was just that OS X was now somehow corrupt. I have now formatted my system and am installing Lepord on a fresh drive. While I do have a backup image of my drive, I decided that I can just restore the files I need and want. So far I am fully unimpressed with Leapord. I have had interrruptions in network connections during pervious software updates, but have NEVER had a problem as it normally fully downloads the upgrade BEFORE it starts installing files. In this case I have ABSOLUTLY no idea what happened. For reasons unknown my install became corrupt and left me with an unusable system. I have done over 40 upgrades from Panther to Tiger (including 4 G3 systems) with no problems like this. My Macbook has mostly all Apple software (some 3rd party video compression tools like iSquint were installed), and I have 2gb of memory, and over 30gb of free space when I did the upgrade on my Core2 Macbook. I still love Apple, but I didn't expect something like this to happen from their systems. I am glad that I have and make my own backups before any upgrade.