My Mac Pro spontaneously restarts

Thanks for your replies and I will certainly look into these suggestions.

But since others are reporting the same problem, and in fact the Apple store was able to reproduce (though not diagnose) the issue, is it possible the problem is with the way the machine is drawing the power and not my electrical current? I don't want to spend 100s of $ on power supplies and a electrician just to discover that "it's not me, it's the computer".

Let me preface, are backups of your system and drives optional or not?

a UPS on a Mac Pro should not be seen as a waste, but as what it is, protection of your $4K and up equipment and will run better and can avoid issues, and make life easier on the PSU. They are not a waste, and only cost $175 and up.

Disk Warrior is a good $90 investment too, no?

The electrician is something, some will come and do a "take a look" for free or a half hour fee, or you could check for yourself.

Yes, yes, of course I see your point and your suggestions are very good and welcome. I should have a UPS regardless. But I don't think the Mac Pro should have to need a UPS in order to merely function properly.

It would be useful to know if anyone who has exhibited the same problem as me (and there seem to be quite a few of us) has a UPS like you describe, and if, by using the UPS, the problem is ameliorated. That would be very helpful information in ultimately troubleshooting the problem.

Right now no one (including Apple) seems to know for certain whether the problem is definitely related to power management, and moreover, whether it's a software or hardware issue, or combination of both.

I had an older G5 PowerMac that was connected to a UPS that the Mac really didn't like and it would reboot whenever the UPS kicked into any kind of mode that would "supplement" the AC power due to a momentary voltage drop.

Ironically the PowerMac would work just fine through the voltage drops without the UPS in place, but its power supply really, really did not like the waveform the UPS generated.

Count me in as another Mac Pro (Early 2008) user who has suddenly had his machine enter a restart shortly after booting up. It happened twice last weekend (both times I had iTunes open and running...) and I tried resetting the PRAM/VRAM, SMC, etc.

Worked fine for the following week until just a few moments ago. Strangely, my Mac Pro restarted on my while I had iTunes open to sync my iPhone. I can't remember if I was syncing my iPhone during last week's restart, but I DO know that iTunes was always running when I had the sudden restarts. Maybe that's here nor there, but I'm noting it nonetheless just in case someone else ends up in a similar scenario.

I'm sorry I don't have any solutions for anyone, though.

My restarts happen even without iTunes running and I don't have an iPhone.

You can see from this thread, that every kind of Mac can get this problem, and there's no solution here either!
http://discussions.info.apple.com/thread.jspa?threadID=2215322&start=0&tstart=0

People seem to try various things, and eventually the problem seems to be solved, and then it starts again. I would argue that this pattern of behaviour is the same whether you try any non-hardware-based fixes or not. In the link above, someone (with an iMac) even had their PSU replaced by Apple and that didn't solve it.

My Mac Pro is due back soon. They thought it might be the PSU or the motherboard that needed replacing. Seems like they were having a best-guess rather than identified the precise cause. In the end, the fact that the fans were also spinning wildly in cunjunction with some of the random restarts, made them think that it was more likely to be a motherboard problem so they have replaced that.

Will keep posting here with updates once I get the Mac back.

Footnote: my Optiarc optical drive also stopped working shortly before it went in for repair. Could that possibly be caused by whatever is causing the restart problem? Also, I'm told the replacement drive Apple sent, arrived faulty. Hence there's a delay while they order another.

Naveen, thanks for your post. Sorry to hear of your troubles as well. My restarts happen without iTunes (or anything else) running.

Clearly this is a problem which affects a sizable number of users. I'm surprised that Apple hasn't heard about it, or maybe they just don't acknowledge it?

I have resorted to not putting my Mac Pro to sleep at all, which wastes energy, but it seems to prevent the restarting problem.

What can we do?

In response to both zoomyzoomy and Phil R.:

I just had my Mac Pro do the sudden restart right after boot-up thing once again, this time without any other application running. No iTunes, no Safari, and no iPhone being hooked up. It's getting worse because this is the first time this issue has happened during back-to-back boot-ups...

At the risk of stating the obvious: this is weird. And annoying. And a little unnerving.

I haven't run memtest on my RAM yet... and I can't do so for a while as I'm going out of town for the holidays for a couple weeks. Maybe the RAM is the culprit... but I've had this RAM for quite a while with no other discernible problems...

If anyone comes across something, no matter how seemingly insignificant, please post in this thread. I'll do the same.

Happy Holidays to everyone.

Another Mac Pro Early 2008 user who has the same problem.
The computer suddenly shuts down with no reason.

Sometimes the computer stay running all the day, sometimes it shuts down one hour after it power on.
Once the first shut down the computer crashes very often.

I ran the apple hardware test and everything is ok.

I don't understand how Apple doesn't have the answer to this problem.

Hello Merlinus and Naveen,

I wish I could offer more than sympathy. For me, the problem almost always happens within about 15 minutes of either startup, reboot, or waking from sleep. Although it has happened maybe a couple of times when the computer has been running longer.

My process has been to turn the computer on, make a cup of coffee and not do anything on the computer for at least 20 minutes, and if all is OK, start working, and leave it on as long as possible without needing to do a restart.

If anyone contacts Apple, please report back. So far no one there officially knows about this issue.

Another mac pro with the same problem. It all started 8 months ago, 1 random restart every month. Over a month ago the computer just became unusable, when you turn it on it restart a few minutes after until a point it restarts when it's booting. I run some tests [hardware & EFI], the results came fine, everything passed.
I thought it was only my mac pro, until I found a lot of people that were experiencing the same problems with there mac pro.
I've search continuously on the web, this topic [basically everywhere], haven't found answers.

Finally, a few days ago I took my mac pro to a technician.

As soon as the technician contact me and tell me what the problem is, I'll write here to keep you guys informed and to know what is the problem you're dealing with.

Cheers,

Thanks, Philip.

I'm away from my Mac Pro now but I wanted to say that when I did have the sudden restart problem, it has (so far) always happened within the first 15-20 minutes of running it, and usually even much sooner. As of the last incident from a few days past, my Mac Pro has restarted on its own about four times, all within nine days.

And @ xjcobx:

Yes, please do post an update when you get your machine back from the shop. I'm curious to see what they say. And thank you in advance.

Once again -- Mac Pro issues aside -- I hope everyone has a great holiday season!

-- Naveen

Please let me know who you contacted at Apple so I may do the same - I too have the same model with the same problem!!!

My email is fljwb@me.com

Thanking you in anticipation

When I contacted Apple about this recently, I spoke with someone named Jonathan who was very nice but said that neither he nor his supervisor had heard of the problem.

Today's report: I turned off the computer because I went away for the holidays. I returned today and started the computer. The computer booted into OS X normally. After about 10 minutes, I had the spontaneous restart. The computer restarted twice more on its own in rapid succession, and then the fans started going full speed.

I did an SMC reset and turned the computer on again. This time, the computer mad a higher-pitched whirring sound and did not boot. I forced the computer off, waited a minute, and turned it on again, and it has been running fine for the last 3 hours.

I'm at a loss for any further suggestions as to what to do, other than at this point just leaving the computer on all the time and restarting only when absolutely necessary, and then waiting a good 20 minutes or so before using the computer again.

I to have done the SMC reset made the fans run at full blast so I powered it off and the mac continues to restart erratically although reading your experience I shall perhaps run SMC one more time .
It seems odd that such a robust computer should be so erratic.
I hope perhaps that there is some firmware on its way to eradicate the problem since it would seem to be a some sort of management system at fault and it seems there are quite a few early 2008 mac pro's with this problem so it would be unlikely that all are running identical software except for Snow Leopard and I really do not wish to roll back to Leopard.
All I want to do is cure this it is very irritating not knowing when the computer is going to restart especially since for the moment I do not seem to be able to download pictures from my camera without a restart.