Apple's quality problems continue ...

As usual, an essential [1] but "minor" OS X update with no significant new features causes widespread issues, though most can be resolved ...

Applers howl over Mac OS fix | Register Hardware

...Overall, the 10.5.6 rough spots are about par for the course for an Apple OS upgrade. However, we at The Reg still recommend that before you attempt the 10.5.6 update - or any update, for that matter - you should create a bootable backup of your entire system, including files and apps. Yes, doing so a time-consuming pain in the wazoo, but as your dear mum used to say, "Better safe than sorry."

Things are bad when reasonable advice includes a full backup bootable backup rather than checking the integrity of routine data backups. Of course since the update addresses issues with corrupt Time Machine backups that can't be restored the backup needs to be done with some other application. Incidentally, it's true that many Apple users have an unhealthy tolerance of Apple's failings. Cognitive dissonance, perhaps?

Apple's due for a leadership change, so it's possible there will be a different approach going forward.

PS. I don't do full system backups prior to these point releases. My procedure is:

1. Wait two weeks from initial release.
2. Check out any sync related products I use (Spanning Sync, etc) and any Preference Pane products. Those often break.
3. Check Macintouch and Apple's discussion forums for any really bad news with products like mine. Especially check the PPC (legacy) discussions.
4. Verify I can do a random file restore from my daily backup.
5. Install first on our MacBook (MacTel machine).
6. A week later install on the primary household machine (G5 iMac).
7. When I install I first do a safe boot restart to clear out caches and test the machine. I then shutdown, and detach all peripherals. I then restart to an admin account and do the install. After install I do a regular restart, then a safe boot, then a regular restart. Tedious, but I attract nasty bugs.