The easiest way to deal with a disruptive issue that occurs after the Mac OS X 10.6.3 update is to simply revert to Mac OS X 10.6.2. Although this option eliminates important security fixes included in Mac OS X 10.6.3, along with any other enhancements, it may be the best option if a problem is interrupting your workflow. There are two easy approaches to downgrading:
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 (current retail discs include Mac OS X 10.6.2), but an otherwise largely intact system. Download the Mac OS X 10.6.2 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 10.6.3, and continue with the process.