Following up on a prior column, Sweeping Up after Snow Leopard, today’s article continues my floor-level look at Mac OS X 10.6. In particular, I want to shine a light on several troubleshooting-related changes to how Snow Leopard updates, reinstalls and relaunches software.

Update to Mac OS X 10.6.1: Software Update menu change. First up is last week’s release of Mac OS X 10.6.1. If you’ve already installed this update, chances are very good that you used the Software Update application to do so. And you likely followed the application’s prompts to install it directly: either by clicking Continue in the initial message or by clicking Show Details followed by Install. When you use this method, there is no Update package left on your drive afterwards. This means that, should you want to install the update again, such as on a second Mac, you’ll need to redownload the update.

In Leopard (Mac OS X 10.5), Software Update’s Update menu offered two useful alternatives to the default Install option: Download Only and Install And Keep Package. With the former choice, the update package downloaded (typically to your Downloads folder) but did not install — allowing you to install the update at any later time and on any volume you selected even when you were not online. The latter choice combined the two other alternatives, both installing the Update immediately and saving the download package for later.

In Snow Leopard, these options are gone. In instead, there is just one new option: Go to Apple Downloads Page, which takes you here.

This new arrangement is not altogether a bad thing. By sending you to the Downloads Page, you presumably get the “combo” version of the update (which combines all previous updates into one package — and is thus not really relevant for a .1 update). In Mac OS X 10.5, all of the Software Update options used the smaller “delta” version. Although delta updates work fine most of the time, the consensus has been that the Combo update is the go-to version if you want to minimize the risk of any problems.

The About the Mac OS X v.10.6.1 Update article still states “that an update size may vary from computer to computer when installed using Software Update.” This implies that Software Update is still using a delta update, different than the standalone installer.

Regardless, the Snow Leopard Software Update option is a bit less convenient than the Leopard method. You now have to locate the desired updates yourself on the Web page. In some cases, a given update may not even be on the Downloads page until a day or so after it is available via Software Update, adding to the potential confusion. You also can’t save multiple packages in one step, as you could with Software Update in Leopard.

Downgrade to 10.6.0 via Install DVD. Moving on, let’s suppose you’ve updated to Mac OS X 10.6.1 and want to return to 10.6.0. Why? Perhaps 10.6.1 introduced a compatibility problem with your favorite application. Whatever. In any case, the question is: Can you do it?

The answer is yes, but in a different way than with 10.5.x. In Leopard, you did this from the Install DVD via an Archive & Install. In Snow Leopard, this option is no longer available. Not to worry. If you simply select to install 10.6 from the DVD, it will do so, smartly replacing the 10.6.1 files with the relevant 10.6 files. It also appears to remove any Apple updates you installed after 10.6.1. For example, it my case, it uninstalled the HP Printer drivers update I had separately added along with 10.6.1. However, it did not uninstall the iTunes 9 upgrade from the previous day.

When you are done with the downgrade, your hard drive will once again be running Mac OS X 10.6.0 (Build 10A432). The only apparent difference between this method and an Archive & Install in Leopard is that there is no residual Previous Systems folder left in Snow Leopard.

On a related note, I checked what would happen if I attempted to re-run the 10.6.1 Update package on a Mac that had already been updated to 10.6.1. The result? The Install utility gave the green light. Presumably, the files are simply reinstalled. This can be useful for when you think files have been corrupted and need to be replaced.

QuickTime 7.6.4. You may have noticed that QuickTime 7.6.4 is out. Apple says that the update adds “support for iTunes 9.” If you’ve optionally installed QuickTime 7 in Snow Leopard, you’re running QuickTime Player 7.6.3. If you want to update to 7.6.4, you’re out of luck. The 7.6.4 update only works with Mac OS X 10.4 and 10.5. If you try to install it on Mac running Snow Leopard, the Installer refuses. Apparently, if you want full iTunes 9 support in Snow Leopard, you need to use QuickTime X. Exactly what iTunes 9 support is missing from QuickTimePlayer 7.6.3? I don’t know; I haven’t looked into this as yet.

If you are determined to get QuickTime Player 7.6.4 onto your Snow Leopard Mac, you could presumably do so by copying it from a Mac still running Mac OS X 10.5. But I advise against this because you wouldn’t be installing all the QuickTime-related Library files. If you were truly determined, you could open up QuickTime 7.6.4 with Pacifist, extract every component and install them in their indicated locations. Again, I advise against this. There’s too great a risk that something will go wrong.

Apple intends to wean Snow Leopard users from QuickTime 7. This is the beginning of the end. Deal with it.

Safe Relaunch gone. In Tiger and Leopard, you may have come across Mac OS X’s Safe Relaunch feature. In essence, if an application crashed and you relaunched it and it crashed again, you had the option to do a Safe Relaunch. Using this option, the application opened using a new default preferences (.plist) file. This essentially checked for the common possibility that a problem with the .plist file was the source of the application crash (as I describe in more detail here). The feature worked perfectly in Tiger, but was buggy at best in Leopard. Apparently, rather than fix the bugs, Apple chose to do away with the procedure entirely. As far as I can tell, there is no longer a Safe Relaunch option in Snow Leopard.