OSX 10.6.3 arrives - some hints on avoiding heartache

Question

The latest update to OSX Snow Leopard is now available through "Software update", and , as a larger "Combo" version (incorporating all the changes made in 10.6.1 and 10.6.2) at http://support.apple.com/kb/DL1017
It is a large update, and people should make proper preparations before installing it.
1) Back up your drive. Everyone has a current back-up of the internal drive anyway, I'm sure! What? You don't? Now is the time to make one if you haven't already! It is not that 10.6.3 in itself is likely to destroy your computer because of improperly written code or the like. It is because like any significant OS update it will install many, many thousands of updated or new files, and if anything is already up with your computer, especially problems with directories or the like, this substantially magnifies the chance of anything that was about to go wrong actually doing so.
2) Make sure you have plenty of free space on the drive. You should have a bare minimum of 10% free space AFTER the installation, preferably 20% or more. Installing many tens of thousands of files can very substantially increase free space fragmentation on a drive, potentially causing a wide variety of problems, including directory issues, operating slowdowns, problems with DVD burning, etc etc. Now is a good time to get rid of the stuff you don't really need or to shift it off to an external. Might even be worth putting in a bigger HD if you are always operating "on the edge" when it comes to space.
3) Boot up from your OS DVD and use Disc Utility from it to "repair disk" on your internal. Installing a major OS update on a drive with corrupted directories can be catastrophic. Running "repair disk" before installing any major piece of software or update can prevent a heap of subsequent misery. If you can't find your OS DVD then at least start up in "Safe Mode" (ie boot up while holding down the shift key). This will also run a directory repair (though it won't provide information about what, if anything, was wrong) and will also flush font caches and a few other things. Once you have done this reboot normally.
4) disconnect all peripherals apart from your battery charger. THis is perhaps less of an issue usually than it used to be, but better safe than sorry.
5) If you are already having problems with your Mac *do not* expect an OS update like this to fix them unless they are specifically mentioned in the documentation that comes with it. In many cases, especially if you have an underlying problem that is caused by directory or OS file corruption of some kinds, installing an update will actually make the problem worse, possibly even preventing your computer from booting. *Sort out problems first*. Don't expect an OS update to resolve them unless it is specifically identified as doing so. There occasionally are situations where the simple act of installing an update will serendipitously replace a "bad" file, especially if you use the "Combo" version of the update, but they are few and far between. Installing updates on computers with problems usually does more harm than good.
6) Opinions differ about the importance of repairing permissions when installing updates. Some people argue that permissions should be repaired before installation. Some say after installation. Some say both. A few say don't bother at all. It doesn't seem to make much difference these days. I usually do it after, though logic suggests it would matter more to do it before hand. Repairing directories (as described in 3 above) before installation really matters MUCH more.
7) Be prepared for some glitches caused by the need to update third party software after the installation of a major update. Be particularly careful about the use of things like disk or maintenance utilities . Check with the maker's website before using such things to make sure that the version you currently have is compatible with the new OS update before using them. Things like third party keyboard and mouse software (especially when they install their own ".kexts" or "system extensions") sometimes cause nasty problems , too. Sometimes software makers will have such things ready to roll out to replace such things as soon as the OS update hits the servers. On other occasions they may not.
8) If a particular piece of software is critical to your work then you may well be better off waiting until it is established by others that it will work with the new OS version or sub-version before updating. (Such problems can make you very glad you that current back-up mentioned in 1) above!)
8) If something, as it very occasionally does, goes wrong, don't panic. Take notes of what has happened as well as you can remember it, think about any "third party" stuff that you may have installed, run disk utility from your OS DVD again to both "repair disk" and "repair permissions" or boot up in "Safe Mode" to see if it fixes the issue, and if not post details of the issue as clearly as possible here. Cries of "OSX Update 10.6.whatsit ate my computer" followed by twenty further cries of "mine too" are usually far less useful, and far less likely to result in a positive solution, than a clear description of your own particular problem, the equipment you are using, third party software that you use, the manner in which you updated, the steps you took before updating, etc etc.
All of this probably sounds a bit draconian, and the vast majority of people update with no problems at all. On the other hand it is better to be safe than sorry. Taking the above steps makes it likely that you will be one of those who don't run into problems, either with the update process itself, or with your computer more generally. The arrival of a major update provides a great opportunity to do the basic checks and maintenance that every computer should have from time to time , to make sure that your back-up is up to date, and to do some of the housekeeping that keeps your computer running smoothly the rest of the time.
Cheers
Rod

Answer 1

You can condense it down to a couple of options, shadowbeast, if you have a computer that is regularly maintained, not over-full, doesn't have much in the way of third party haxies installed, has had its directories checked recently, don't try to install the update while simultaneously running other software, etc etc. Trouble is in many cases such parameters aren't met!
Using an update situation as an opportunity to undertake the general maintenance that should be done every month or so on any computer , (even if it is a Mac!) helps to forestall many other problems, too, as well as helping to ensure that the update process goes smoothly.
I agree that the "Combo" update can be a good idea, sig, and I've usually done so in the past myself. In some circumstances it can certainly help to overcome problems that have arisen along the way. These days, however, the updates themselves tend to be very large (in this case the "combo" version is over 800 MB in size) and I'm very aware that many , many people use the smaller Software Update versions. These seem to be less problematic than they used to be in the past, though if anything is problematic after the installation downloading the Combo and re-installing it over the top of the SU version is a very good idea.
I've been trying the SU updates regularly myself since SL arrived on the scene, and all have gone smoothly. Mind you, this has been on a couple of pretty well maintained machines.
Cheers
Rod