No sound after update on Macbook Pro

Question

Hi all,
after running the latest software update on my MacBook Pro (early 2007) the sound stopped working (except for in iTunes). I suspect it has something to do with the iTunes 9 / QT update. Also system preferences freezes when I try to access the sound settings...
Any ideas?
Thanks,
Ulf

Answer 1

These two links have references to sound issues:
http://discussions.apple.com/thread.jspa?threadID=1909270&tstart=0
http://discussions.apple.com/thread.jspa?threadID=1933397&tstart=0
However, since this is associated with an update it is possible something more extensive is involved. I would:
Boot from installer disk and verify hard drive is okay with Disk Utility > First Aid.
If okay, boot from computer and use Disk Utility on main drive to repair permissions. Check sound.
If still bad, back up critical files, try reinstalling updates one at a time repairing permissions in between.
If still bad, resort to Archive and Install with preserve users & settings.
Updating
Certain steps appear to minimize the risk of an update producing problems.
Number one is to make sure you have a bootable clone backup of your computer in case you do need to back out of it again. This is the only guaranteed way of not having to worry about the results of an update.
Some like to boot from their installer discs or an external backup and verify (and if necessary repair) their internal drives as well as drive permissions. This is done with Disk Utility. You can verify a drive while booted from the same drive but sometimes this produces spurious errors. Repairing a drive (if necessary) has to be done while booted from another disk. Permissions repair can, and is probably best, done when booted from your internal drive.
[Resolve startup issues and perform disk maintenance with Disk Utility and fsck|http://docs.info.apple.com/article.html?artnum=106214]
[Using Disk Utility in Mac OS X 10.4.3 or later|http://docs.info.apple.com/article.html?artnum=302672]
[Disk Utility's Repair Disk Permissions|http://docs.info.apple.com/article.html?artnum=25751]
You can also go to the step of booting into safe mode to do the install.
[Mac OS X: Starting up in Safe Mode|http://docs.info.apple.com/article.html?artnum=107393]
[What is Safe Boot, Safe Mode? (Mac OS X)|http://docs.info.apple.com/article.html?artnum=107392]
[Safe Boot takes longer than normal startup|http://docs.info.apple.com/article.html?artnum=107394]
I like to download the update onto my computer and install it from there rather than let Software Update do it. I know a few people who had problems with doing the update via software updater found a manual install to work.
Repair permissions again afterward.
It helps to only install one update at a time and to run the computer for a while to make sure it is behaving well.
The more cautious even like to unplug third party peripherals (see [comment by BDaqua|http://discussions.apple.com/message.jspa?messageID=9040746#9040746]).
Almost all of the above steps (except backup) have been questioned as to necessity because probably many people have done successful updates without doing them. I say they can't hurt, they can very likely do good (especially if your computer isn't regularly maintained), so why not do them to be safe.
[BDaqua's comments on updating problems|http://discussions.apple.com/message.jspa?messageID=8948595#8948595]
[Baby Boomer's comments on updating problems|http://discussions.apple.com/message.jspa?messageID=9025760#9025760]
[Klaus1's post on updating and removing updates|http://discussions.apple.com/message.jspa?messageID=9856275#9856275]