Feedback on Successful updates

Question

Software update has just informed me about the 10.5.6 update being available for my MacBook Pro, currently running 10.5.5. If I understood some of the posts where problems were encountered the size of the update package was not what was expected. I checked /Libary/Updates and I have a 190.9 MB package that will be installed when I tell Software Update it is OK to update. Is that the correct size package for my situation?
Sounding like I should run Check Permissions before trying to apply this based on other posts in these forums. I am inclined to wait a few more days to see if further information about this update and why people seem to be having problems comes to light. At this point the problem updates seem to be sort of random, at least in my reading of the various posts.
Has anyone come across a reasonable explanation as to why a significant number of users are having problems with this update?

Answer 1

FWIW, I downloaded the Mac OS X 10.5.6 Update using the "Download only" option of Software Update since I was going to apply it to more than one Mac & saw no reason to download it more than once. (As you might know, if you do not choose this option, which downloads the MacOSXUpd10.5.6Patch.pkg file to your Downloads folder, the downloaded update will be deleted from /Libary/Updates once it is installed.)
This file is 190.9 MB, just like the file you downloaded. I have successfully used it to update both my iMac G5 & my MacBook. (FYI, the download was done with the G5 & I updated it using Software Update, which recognizes that the download was already in the Downloads folder. For the MacBook, I copied the file to it & opened it, which launches the Installer app. With the first method, the first restart is forced; with the second I had to click "OK" since the Installer app is running normally. Otherwise, the installations were identical, each requiring two restarts before the process was complete.)
Thus, I do not think the size difference between the "delta" disk image (dmg) version downloadable from Apple's downloads site & the package (pkg) version is significant. Two very different Macs; two somewhat different install methods; 100% success for both.
Like Dave Sawyer, I believe the vast majority of update problems can be traced to preexisting problems in the installation of the prior version of the OS, in the presence of incompatible third party items, in the file system of the startup drive, or in the hardware (especially with RAM). I have intentionally left permissions problems off this list -- I do not think that is a significant source of update problems because the process normally runs as root.
Anyway, I do nothing more than making sure my data is backed up before applying an update. I sometimes clone the startup drive of my G5 if I am using it for a project with a deadline (so that should something go wrong I can reboot from the clone & finish the project on time). I sometimes run Disk Utility's "Verify Disk" test beforehand if I haven't done that in a while, especially if I suspect a power failure has caused the Mac to shut down abnormally, which can cause file system corruption.
Perhaps this works for me (& it always has) because among other things I do not add any third party "enhancers" or "Haxies" to my Macs & run the verify disk test often enough to catch any creeping disk corruption before it gets serious enough to clobber the OS. I did add non-Apple RAM to my G5, but I used Rember to test it thoroughly before trusting it. Whatever the reason(s), I have never hesitated to use Software Update for OS updates. For me at least, it "just works," exactly like I expect it to.