It used to be Mac upgrades were straight forward and safe, but no longer. I'm continually experiencing some problem or another, though fortunately most are pretty easy to remedy — here's another and my most recent.
I have an extensive backup strategy which includes backing up to two different external drives. When I upgraded to 10.5.6 I had no issues with Time Machine on the first of the drives but when I got to work today I was greeted with this lovely and informative message:
You do not have appropriate access privileges to save file ".0022xxxxxxxx" in folder "Island".
It's an easy fix, open iTerm or Terminal and follow along:
$ cd /Volumes/{volume name}
$ sudo chown $USER {file name}