Sudden shutdown

Mine went for a couple of days with only one shutdown. Today, before 11:30, I had four.

Ken... please keep us informed on how downgrading to 10.4.6 is working. This is really becoming an issue for me. I'm in the middle of my busiest time of year and can't afford downtime.

Has it been established yet what is causing this problem? Does a new power supply fix it?

Since I downgraded to 10.4.6, I haven't experienced a sudden shutdown once.

Admittedly, I only experienced two days of it -- much less than what some folks are discussing here. Also, immediately after downgrading I allowed Software Update to install all the updates it wanted except for the OS. That included Java, iTunes and Quicktime; given the fact that some of you think this might have been iTunes-related, I don't know if that might have had some effect as well.

I hope Apple figures this out and does something before I buy a new power supply!

Has Apple posted anything, anywhere?

I tend to agree, the only possibility is that a certain component common to all of our G5s, are starting to fail after a certain amount of usage. Or possibly a software problem, related to a specific component only found in G5s. I really doubt this has anything to do with iTunes or QuickTime or else many people besides G5 owners would be experiencing the same problems. iMac users, G4 users, maybe even laptop users.

Since this is isolated to one machine type for the most part, and seemingly within 2 or 3 revs / generations, it's more likely a firmware or software related problem. That is some bit of code or extension that is only installed on G5s.

I'm running 10.4.8 since the day it came out, recording QT videos almost every day, listen to iTunes every day (though I don't have the startup item present), and I never experienced this problem until today. My G5 is a dual 2GHz of the original variety, purchased in the fall of 2003.

To be clear, here's what happens:

1. Push start button.
2. Machine chimes, and begins its boot process.
3. Goes for about 20 seconds, gets to the grey screen, pauses and shuts itself down.

• Disk Verifies properly, no Permissions issues, resetting LMU and PRAM does not help.

• When I start into Safe Mode (hold down shift key at boot) everything works fine.

• Made sure all sleep modes, etc are off. No difference.

• APS Back-ups battery is fully charged and almost never kicks in due to power outage. When it does I shut everything down immediately. None this year. This isn't a battery backup problem.

I also doubt massive hardware failure, as Safe Mode would not be a way around that most likely, especially if power related. Odd thing is, when I shut down from Safe Mode, it's almost immediate. I could be imagining things but it usually takes 20 seconds or so to shut down, even in Safe Mode. Right? Obviously shutting down from Safe Mode is going to be quicker than Normal Mode, but not that much faster....

Also I would encourage everyone to NOT have their motherboard or other extensive repairs done until more is known, as this is almost certainly not that kind of a problem. This is some type of power-related firmware or software bug most likely, or at worst a partial PSU failure as being noted in that extension program. The odds that anyone needs to have a board replaced is pretty low IMO and is likely to cause you other problems you don't need.

Update:

Running the following maintenance routines from Onyx does not help but does manage to get the computer "Stuck" in gray screen mode, rather than a shut down (equally useless).

Daily, Weekly, Monthly Script
Launch Svcs Update
System Optimization
System, User, Kernel Cache Cleaning

Having used Macs for over 15 years and being able to solve nearly any system problem on a variety of Macs (not related to motherboard failures - which I'm still almost certain this is not), this one really has me scratching my head.

I guess the logical question to ask is, what does Safe Mode turn off, relating to power usage, than Normal Mode has turned on? Answer that and we may be onto something.

Thanks for the update.. thing is though, I've been running 10.4.7/10.4.8 with iTunes for months. If it's iTunes why is this happening now? People should've had the problem right away. The other thing is, by going back to 10.4.6 you're changing a lot of system files so it becomes difficult to say that it's iTunes and not the system change, that's causing/fixing it.

The irony is I just backed up cleared my drive and re-installed, but I didn't stay at 10.4.0. I did the software updates. Not sure if there's any way to "revert" but I'll check the system downloads page.

I still can't get past the fact that Safe Mode removes the problem. To me this means it has something to do with one of Apple's extensions, not hardware failure. I mean, if a mechanical thing fails, holding back an extension at startup is not going to make that mechanical thing suddenly work. : )

This one is really irritating I have to say.

Wierd. Thing is, I never had the iTunes startup item present during all the times before I had the problem, even though I used iTunes almost constantly.

Second update. After clearing everything and going to a straight OS X install with no 3rd party stuff and double-checking permissions, etc... now once booted in Safe Mode... my G5 refuses to... SHUT DOWN.

IOW, if I try to turn it on normally it shuts itself off. If I go to Safe Mode, it won't shut off even if I want it to, nor will it restart from Safe Mode.

F U B A R

Apple needs to get on this immediately. This is garbage.

If iTunes Startup item happens to be what salvaged your setup, then I believe you have a different problem that exhibits the same symptoms. Since last posting I have gone back to 10.4.0 again. It will not restart without shutting down from there.

I tried updating to 10.4.5, again it would neither restart after, nor power up manually.

I tried updating to 10.4.6, same result.

People don't waste time reinstalling system software at this point unless you have plenty of free time. Most likely it will not solve your problem, nor will removing the iTunes startup item from your login items. This is very definitely related to power management and possibly the firmware.

Another (ugly) possibility is that we're see one of the first OS X viruses, perhaps planted in NVRAM so that clearing the HD makes no difference. There is obviously some type of erroneous shutdown command being issued during the boot process. Actually not even a shut down command, more like a kill power command since there is no "wind down" before it happens as in a normal shut down.

I am going to take this to the local Apple Store for a hardware diagnostic and see what that results in. This is one of the most frustrating problems I've ever dealt with in over 15 years of usage, consulting and trouble-shooting. Usually I'm the guy that solves other people's problems (for money at one time) but this is bad....

Actually I do, but removing iTunes Startup item and booting from multiple, clean installed, pre-10.4.7 systems does not solve the problem. Oddly, I saw some information about this here

http://www.gibbilicious.com/gibbilicious/2006/02/troubleshootingthemysterious.html

and at XLR8 (most of which seemed pretty anecdotal), and there was the thought it could be due to improperly seated RAM and/or Video boards. So I went in, reseated the board (which was OK to begin with), and in the process had my computer unplugged for about an hour.

When I plugged it all back in (minus 3rd party stuff), I didn't expect it to boot, but it did, sadly I thought the trick immediately would then be to do a proper shutdown so the system sees that each time it starts up. Of course, the shut down took .3 seconds and then when I tried booting I'm stuck again. Where's the blind rage smiley when you need it?