Most users will install the recently released Mac OS X 10.6.4 without a hitch, but a handful will likely experience problems that range from minor annoyances to workflow interruptions.
There is a routine that will eliminate 99% of show-stopping issues after any incremental Mac OS X update. If you’re experiencing such a problem (i.e. a disruption of your workflow), start with option #1 and continue to work your way through the process until your problem is resolved.
Option #1 — try this first
Download the Mac OS X 10.6.4 combo updater, which weighs in at a hefty 887MB but is a troubleshooting godsend. Quit all open applications and run the installer.
Option #2 — if option #1 fails, try this.
Booting your Mac in Safe Mode then simply restarting normally is one of the most overlooked, most effective procedures for solving a variety of issues after an incremental Mac OS X update. The reason for its efficacy: booting in Safe Mode forces a disk directory check, clears potentially problematic cache files and performs other routines, detailed here.
To boot in Safe Mode, hold the Shift key while your Mac is starting up. After booting in Safe Mode, simply restart normally (without holding the Shift key) and check for persistence of the issue.
Option #3 — if options #1 and #2 fail, try this.
Downgrade to Mac OS X 10.6.3. Although this option eliminates important security fixes included in Mac OS X 10.6.4, along with any other enhancements, it may be the best option if a problem is interrupting your workflow and options #1 and #2 prove ineffective.
Reinstall (if you don’t have a current Time Machine backup). Insert your Snow Leopard installation disc, then restart while holding down the C key. When prompted, choose the normal “Install” option. Make sure to select “Preserve Users and Network Settings.”
After installation, you’ll be left with an earlier iteration of Mac OS X 10.6.x (most current retail discs include Mac OS X 10.6.2), but an otherwise largely intact system. Download the Mac OS X 10.6.3 combo updater and apply it if your disc has an earlier version of Snow Leopard. You may need to restore some saved username/password information, browser information, etc.
Restore from Time Machine Backup. If you have a current Time Machine backup,connect the Time Machine backup disk, then insert your Snow Leopard installation disc, then restart while holding down the C key. After selecting your language, go to the Utilities menu and choose“Restore from Time Machine Backup.” Choose your Time Machine backup disk and choose a backup iteration directly prior to when you installed the Mac OS X 10.6.4, and continue with the process.