Hopefully, resetting the System Management Controller should fix that issue; here is some information on it:
And here are the instructions:
1. Shut down the computer.
2. Unplug the computer's power cord.
3. Press and hold the power button for 5 seconds.
4. Release the power button.
5. Attach the computers power cable.
6. Press the power button to turn on the computer.
After that, you might also want to try a PRAM reset:
Thanks for your help.
I did what you suggested but the problem remains the same: iMac shuts itself off and then shuts itself on and off again if I'm not logged in, and again and again.
Please see Console's log below:
Feb 2 10:00:24 localhost com.apple.launchd: * launchd has started up. *
Feb 2 10:00:30 localhost mDNSResponder: mDNSResponder mDNSResponder-258.14 (Nov 18 2010 14:18:32) starting
Feb 2 10:00:31 localhost blued: Apple Bluetooth daemon started
Feb 2 10:11:50 iMac-2 configd: PMConnection IPConfiguration com.apple.powermanagement.applicationresponse.slowresponse 2407 ms
Feb 2 10:11:50 iMac-2 configd: PMConnection AirPort configd plug-in com.apple.powermanagement.applicationresponse.slowresponse 2409 ms
Feb 2 10:11:57 iMac-2 mDNSResponder: Failed to register with SPS, now sending goodbyes
Feb 2 10:11:58 iMac-2 configd: PMConnection mDNSResponder com.apple.powermanagement.applicationresponse.slowresponse 10854 ms
And then iMac turned itself on (no preset in System Preferences):
Feb 2 11:50:20 localhost com.apple.launchd: * launchd has started up. *
Feb 2 11:50:25 localhost DirectoryService: Improper shutdown detected
Feb 2 11:50:27 localhost blued: Apple Bluetooth daemon started
Feb 2 12:01:42 iMac-2 configd: PMConnection IPConfiguration com.apple.powermanagement.applicationresponse.slowresponse 749 ms
Feb 2 12:01:43 iMac-2 configd: PMConnection AirPort configd plug-in com.apple.powermanagement.applicationresponse.slowresponse 1236 ms
Feb 2 12:01:52 iMac-2 configd: PMConnection mDNSResponder com.apple.powermanagement.applicationresponse.slowresponse 10005 ms
I really don't know what to do.
(This problem being extremely annoying when trying to work with my iMac, I'm considering contacting Apple but this is the last thing I want to do - a conversation with AppleCare's staff is 90% of the times completely useless and takes hours and hours for stupid questions).
If you have any idea, please let me know.
Well, since you're still covered by warranty, and if you don't want to call Apple, why not make an appointment at your nearest Genius bar? Be sure to take along print-outs of your error messages and a list of troubleshooting steps you've already taken. At least you should be able to get a definitive diagnosis that way.
Well, either call Apple or, if there is an AASP in your area, you could take it there. If you have Applecare, you are covered for 3 years; if you just have the basic warranty, you have 90 days of free phone support and a full hardware warranty for a year.
Since no one else has chimed in here, I'm guessing that everyone is as stumped as we are; that's why I suggested contacting Apple.
Okay, I'll call Apple though.
But I'll do it my way: certainly not prepared to spend 2 hours with the Apple phone guy/girl. I'll go directly to an Apple approved workshop where the serial number of my machine is enough for them to take care of it since it's still covered by warranty.
The problem with those guys is that if they happen to find the problem is related to a piece of software I've installed, they gonna charge me a bomb, warranty won't apply... Hence my wandering on the fora.
That being said, I really have no idea of who might have broken what and I'm no expert, I'm no geek, I only tamper with Terminal when necessary and following the guidance of people who perfectly know what they are doing.
Did you buy the computer new from Apple or Apple refurbished? If you're still under warranty, they should not be any charge. If you restart manually and use your computer, does it turn off? The first thing that came to mind, is the computer shut down because of overheating. Do you have any temperature and fan speed software like Hardware Monitor? I've always had good response from the phone help. You can politely ask to be transferred to higher tier technical person.
I bought the computer new from an official Apple Reseller last june.
If I restart manually and leave the iMac on the login panel (users panel), it turns off and after about an hour and a half turns itself on again and off and on and so forth.
For temperature control I'm using iStat Menus, please find below the actual fans speeds:
Hard Drive: 1098rmp
Optical Drive: 989rpm
As for the Apple Assistance, I've always been very polite but several times (not always) been harshly treated. What's more, in my area everybody knows the way those Apple phone persons behave and tries to avoid phoning if possible (Unfortunately, this not the USA where the customer is king; over here the customer is... well, just... No comments.).
Sorry to hear that; now, the initial person - in the US - also is not the most knowledgeable and I usually insist that I be bumped up to tier II (in the US, it's called a Senior Advisor). You might try that; also, when they want you to go through prescribed troubleshooting methods, tell them you've already done that and would like to speak with someone experienced to tell you what the error codes are.
Thanks Barbara for letting me know what to say ("the error codes", very good indeed):-)
I might try that but beforehand (or right before probably), I should purchase an Apple Care which, as a good practice, I generally don't do until the last minute (11th month) since the coverage is NOT transferable (which is, to my opinion, a rip because in case my machine is stolen or lost or broken by accident I might buy the same type, I mean iMac coverage should cover you if you replace your iMac by a new one during the 2 additional years of warranty).
In the meantime, if somebody comes up with the miracle solution, please be my guest!
+coverage is NOT transferable+
Applecare covers the machine - not you, so it is transferable to the new owner if you sell your Mac. You can also usually talk to Apple about a partial credit if Apple replaces your machine due to a defect or it should also be possible if your Mac is stolen or you throw it out of a window .
Well, personally I wouldn't throw the iMac out of my window but you never know nowadays, don't you?
Anyway that's good to know.
In the meantime, let's keep our fingers crossed and hope that someone comes up with the solution to my problem.
I've been browsing several fora with same topic but the mentioned problems were either not solved or different from mine.
The problem you are having seems to be a bit different from the “random shutdown” problems due to RAM incompatibility that’s widely reported in this Discussion. But since I see “improper shutdown detected” in your console log, I think what your machine is doing is randomly shutting down, and then turning itself on again because you have your setting on to “automatically restart after power outage.”
Check the RAM you have. Although the shutdowns are generally associated with people who upgrade to 16GB, it does happen with 8 or 4GB and with factory-installed RAMs as well. Since you are hesitant about calling Apple, try the RAM switch because it’s such a simple procedure and the effect is immediate.
Pull out the RAM from the slots, and see which RAMs you’ve got.
The factory-installed RAMs in iMac can be made by Samsung, Hynix, or Micron Technology. Whatever RAMs you get, change with Samsung RAM you purchased from a reputable seller.
4GB RAM will cost you about 40 US dollar or so (about 4200 yen in my part of the world). If it doesn’t work it will be extra cost, but I think you can sell RAM sticks fairly easily.
So just give it a try. It’s much easier than lugging your iMac to the store and sitting around for a week to get it fixed (in my case, Apple could not fix it). If this doesn’t work, then call Apple.
Checking the RAM is a great idea (although bad RAM usually causes freezes or crashes, but you never know) - now, your profile shows you have the stock 4 GB? If that is so, you can do a couple of things:
Check the RAM in System Profiler to see if it shows "OK"
Check all your hardware including the RAM with the Apple Hardware Test - info is here:
(run the extended test)
Neither is 100% sure to pick up problems; there is an app you can download which is more thorough:
If you've added RAM, take those out and see if it works better.
If you want to buy RAM, do it from a reputable seller such as OWC (macsales.com) or Crucial - iMacs are very finicky about their RAM quality.