As always I have three backups of critical data ( in different locations). I also make a drive copy, using SuperDuper, before I start an OS upgrade. It’s a good thing I did.
The upgrade of the iMac went smoothly.
The upgrade of the Macbook Pro did not.
Somehow the 10.6 upgrade trashed the partition on the hard drive. If I hadn’t had the hard drive copy I would have been in trouble. Instead it just took a few hours to copy all the data back over to the MBP after the 10.6 install.
ALWAYS make backups of your data. It’s not a matter of if, but when you’ll need that backup. Yes, backing up is a pain, but it’s not nearly as painful as discovering you just lost your hard drive and everything on it and don’t have a backup.