Why Do My Applications Crash After Updating 10.8.5?

Question

I was notified of an OS X available update to 10.8.5 [12F37] (from 10.8.4 [12E55]) yesterday evening [September 17th, 2013] and per my SOP I initiated the update.  My iMac restarted and allowed the Mac App Store to do its thing... The computer restarted...  Everything was fine until I tried to open an application.  The app crashed with a report 1-2 seconds after my clicking the dock icon.  Ok, So I tried it again just to be sure...  It crashed.  I tried a variety of different applications on my machine, some crashed out-right, a few opened "normally", while Safari would open and begin loading a page, yet never finish.  Safari just sits... halfway loaded progress bar and a blank screen.  I have noticed a process called "kernel_task" that is sending and recieving millions more messages than any other process while my iMac is running.  This seems like a prime suspect for the problem, but I can get no additional information about just what exactly this process is or what it is doing (this is obviously over my head).  I would try to force quit the process to see if that helps at all, but Activity Monitor will not allow me to do so...  I'm guessing it's an integral part of the operating system [PID 0, whatever that may be] that might be running amuck.
I have seen several posts on the forums regarding similar issues, but every post I've seen pre-dates this particular update by a good margin and almost every one has not been resolved.  I have investigated the options provided in the small handfull of posts that wore the green bubble-badge of resolution with no success.
I am ready to restore my system from an earlier backup just so I can continue to work on some very important, active projects, but that will not correct this problem as with every update that Apple releases, I am compelled to trust them and complete the update on my system to keep it up-to-date.
Has anyone else out there had this current issue?  Has any gurus out there have any additional trouble shooting techniques that I could be guided by to help track down this "bug"?

Answer 1

Please read this whole message before doing anything.
This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.
The purpose of the test is to determine whether the problem is caused by third-party software that loads automatically at startup or login, by a peripheral device, or by corruption of certain system caches. 
Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards. Boot in safe mode and log in to the account with the problem. Note: If FileVault is enabled on some models, or if a firmware password is set, or if the boot volume is a software RAID, you can’t do this. Ask for further instructions.
Safe mode is much slower to boot and run than normal, and some things won’t work at all, including sound output and  Wi-Fi on certain iMacs. The next normal boot may also be somewhat slow.
The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin. Test while in safe mode. Same problem? After testing, reboot as usual (i.e., not in safe mode) and verify that you still have the problem. Post the results of the test.