Symptoms: After updating to 10.5.6, Mail may encounter such problems as unexpectedly quitting, not being able to quit out of Mail and problems loading messages.  
Solution: Apple has acknowledged this issue and provided an update “fix” for Mail.  Run Software Update, if Mail Update 1.0 appears, go ahead and run the update.  Reboot and test. [...]

Problem:  When setting “Single” spacing in the formatting preferences, Word seems to be stuck in double-space mode.    Here is the fix until and if Microsoft decides that this is an issue and not a good idea:
Solution:  Go to the Format menu at the top bar and select, Style, from the drop-down menu that appears.  Normal [...]

Problem: Just came across this with a client’s machine the other day.  She got back her machine from Apple after they’d done a data transfer and there are a slew of issues including this one.  The date and time will not set correctly.  I noticed that the time was off, so went into System Preferences [...]

Symptoms: In OS 10.5.6 Can’t copy or paste anything in Word, Text Edit or any other applications.  Can’t drag icons either.  
Solution: It’s a corrupt Finder.  Trash com.apple.finder.plist, reboot.

Stumbled upon this when I was doing a routine set up for a client:  Apparently you can no longer register your Applecare Agreement via Apple’s site if you purchase your products through a reseller.  You have to either fax or email your proof of purchase of the Apple product(s), along with the Applecare s/n & [...]

symptom: items on desktop will refresh (ie. disappear, then reappear) , causing the finder to disfunction.  
solution: go to home/library/preferences and locate com.apple.sidebarlists.plist and move it to the trash, log out of user and log back in.