68      iPhone_iPad_Mac_apple

iMac (Retina 5K, 27

My iMac has been randomly restarting itself (about once a day) when it is idle.  Has anyone else experienced the same problem?  I found a YouTube video and it is exactly what happened to my iMac:  https://www.youtube.com/watch?v=ka7lUIeiH5E

I witnessed it once -- the computer was on (not sleeping) with the display off, nothing CPU/GPU intensive running.  I suddenly heard a chime and saw that the computer restarted itself.  I logged in.  There was no pop-up window.  I launched Console and did not see anything unusual before the restart.

More information:

1. The computer is idle when restart happens.  Nothing on the computer indicates it overheats.  Display is off (due to inactivity) and fan is quiet.
2. There is no trace of software shutdown, kernel panic or crash.  System log shows normal activities and then a sudden BOOT_TIME entry, as if someone yanks the power cord.
3. It is not a power failure because the computer should be off if it is really a power failure.  "Start up automatically after a power failure" is not checked.
4. It started to happen after I came back from a trip and upgraded my iMac to the latest Mac OS X five days ago.  This computer was purchased last October and I had never seen something like this until a few days ago.

The comments on the YouTube video suggest a total replacement, but I'm reluctant to do so if it turns out to be a software/firmware problem that can be fixed. -- The computer is heavy and the nearest Apple Store is not very close, not to mention the backup/restore efforts.

Thanks

Seems to be an issue with 10.11.4. Presumably you were not having this problem prior to installing 10.11.4

Other threads on this issue here: 5k iMac reboots on it's own after installing 10.11.4   Unexpected Reboots

I think that it's highly unlikely that it's hardware as all signs point to a software issue (no issues prior to updating to 10.11.4 and everyone is reporting the same behavior (unexpected random reboots) and error code ("previous shutdown cause -128" - which no one seems to know what that means exactly) after updating to 10.11.4. In any event, hardware problems usually present themselves right out go the box or after you tinker with the machine in some way such as installing ram, adding peripherals, etc and afterwards you begin to encounter unexpected behavior. None of that seems to be happening with this issue.

Thanks for the information about other threads.  I did a search on "restart" and did not find any threads, so I started a new one.  I guess I should have searched "reboot".

I really hope it's a software issue and there is a fix soon.  In my case, the reboot/restart also happens when I'm not using my computer.  So far it has not happened I'm actively using the computer.  I changed the screen saver but don't know if it's going to make any difference.

1. This procedure is a diagnostic test. It changes nothing, for better or worse, and therefore will not, in itself, solve the problem. But with the aid of the test results, the solution may take a few minutes, instead of hours or days.

The test works on OS X 10.8 ("Mountain Lion") and later. I don't recommend running it on older versions of OS X. It will do no harm, but it won't do much good either.

Don't be put off by the complexity of these instructions. The process is much less complicated than the description. You do harder tasks with the computer all the time.

2. If you don't already have a current backup, please back up all data before doing anything else. The backup is necessary on general principle, not because of anything in the test procedure. Backup is always a must, and when you're having any kind of trouble with the computer, you may be at higher than usual risk of losing data, whether you follow these instructions or not.

There are ways to back up a computer that isn't fully functional. Ask if you need guidance.

3. Below are instructions to run a UNIX shell script, a type of program. As I wrote above, it changes nothing. It doesn't send or receive any data on the network. All it does is to generate a human-readable report on the state of the computer. That report goes nowhere unless you choose to share it. If you prefer, you can act on it yourself without disclosing the contents to me or anyone else.

You should be wondering whether you can believe me, and whether it's safe to run a program at the behest of a stranger. In general, no, it's not safe and I don't encourage it.

In this case, however, there are ways for you to decide whether the program is safe without having to trust me. First, you can read it. Unlike an application that you download and click to run, it's transparent, so anyone who understands the code can verify what it does.

You may not be able to understand the script yourself. But variations of it have been posted on this website many times over a period of years. Any one of the millions of registered users could have read the script and raised the alarm if it was harmful. Then I would not be here now and you would not be reading this message. See, for example, this discussion.

Nevertheless, if you can't satisfy yourself that these instructions are safe, don't follow them. Ask for other options.

4. Here's a general summary of what you need to do, if you choose to proceed:

☞ Copy the text of a particular web page (not this one) to the Clipboard.

☞ Paste into the window of another application.

☞ Wait for the test to run. It usually takes a few minutes.

☞ Paste the results, which will have been copied automatically, back into a reply on this page.

These are not specific instructions; just an overview. The details are in parts 7 and 8 of this comment. The sequence is: copy, paste, wait, paste again. You don't need to copy a second time.

5. Try to test under conditions that reproduce the problem, as far as possible. For example, if the computer is intermittently slow, run the test during a slowdown.

You may have started up in safe mode. If the system is now in safe mode and works well enough in normal mode to run the test, restart as usual before running it. If you can only test in safe mode, do that.

6. If you have more than one user, and only one user is affected by the problem,, and the affected user is not an administrator, then please run the test twice: once while logged in as the affected user, and once as an administrator. The results may be different. The user that is created automatically on a new computer when you start it for the first time is an administrator. If you can't log in as an administrator, test as the affected user. Most personal Macs have only one user, and in that case this section doesn’t apply. Don't log in as root.

7. Load this linked web page (on the website "Pastebin.") Press the key combination command-A to select all the text, then copy it to the Clipboard by pressing command-C.

8. Launch the built-in Terminal application in any one of the following ways:

☞ Enter the first few letters of its name ("Terminal") into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad and start typing the name.

Click anywhere in the Terminal window to activate it. Paste from the Clipboard into the window by pressing command-V, then press return. The text you pasted should vanish immediately.

9. If you're logged in as an administrator, you'll be prompted for your login password. Nothing will be displayed when you type it. You will not see the usual dots in place of typed characters. Make sure caps lock is off. Type carefully and then press return. You may get a one-time warning to be careful. If you make three failed attempts to enter the password, the test will run anyway, but it will produce less information. If you don't know the password, or if you prefer not to enter it, just press return three times at the password prompt. Again, the script will still run.

If the test is taking much longer than usual to run because the computer is very slow, you might be prompted for your password a second time. The authorization that you grant by entering it expires automatically after five minutes.

If you're not logged in as an administrator, you won't be prompted for a password. The test will still run. It just won't do anything that requires administrator privileges.

10. The test may take a few minutes to run, depending on how many files you have and the speed of the computer. A computer that's abnormally slow may take longer to run the test. While it's running, a series of lines will appear in the Terminal window like this:

    Test started

        Part 1 of 4 done at: … sec
        …
        Part 4 of 4 done at: … sec

    The test results are on the Clipboard.

    Please close this window.

The intervals between parts won't be exactly equal, but they give a rough indication of progress.

Wait for the final message "Please close this window" to appear—again, usually within a few minutes. If you don't see that message within about 30 minutes, the test probably won't complete in a reasonable time. In that case, press the key combination control-C or command-period to stop it. Then go to the next step. You'll have incomplete results, but still something.

In order to get results, the test must either be allowed to complete or else manually stopped as above. If you close the Terminal window while the test is still running, the partial results won't be saved.

11. When the test is complete, or if you stopped it manually, quit Terminal. The results will have been saved to the Clipboard automatically. They are not shown in the Terminal window. Please don't copy anything from there. All you have to do is start a reply to this comment and then paste by pressing command-V again.

At the top of the results, there will be a line that begins with the words "Start time." If you don't see that, but instead see a mass of gibberish, you didn't wait for the "close this window" message. Please wait for it and try again.

If any private information, such as your name or email address, appears in the results, anonymize it before posting. Usually that won't be necessary.

12. When you post the results, you might see an error message on the web page: "You have included content in your post that is not permitted," or "The message contains invalid characters." That's a bug in the software that runs this website. Please post the test results on Pastebin, then post a link here to the page you created.

If you have an account on Pastebin, please don't select Private from the Paste Exposure menu on the page, because then no one but you will be able to see it.

13. When you're done with the test, it's gone. There is nothing to uninstall or clean up.

14. This is a public forum, and others may give you advice based on the results of the test. They speak for themselves, not for me. The test itself is harmless, but whatever else you do may not be. For others who choose to run it, I don't recommend that you post the test results on this website unless I asked you to.

15. The linked UNIX shell script bears a notice of copyright. Readers of ASC may copy it for their own personal use. Neither the whole nor any part may be redistributed.

Thanks for the script.  My iMac rebooted itself again this morning.  I ran your script to collect the information as soon as I got a chance.  I didn't see anything unusual prior to the reboot.  Here are a few entries from the log up to the reboot:

4/9/16 8:44:21.350 AM locationd[78]: Location icon should now be in state 'Inactive'

4/9/16 8:48:36.000 AM syslogd[42]: ASL Sender Statistics

4/9/16 8:58:36.000 AM syslogd[42]: ASL Sender Statistics

4/9/16 8:59:45.000 AM bootlog[0]: BOOT_TIME 1460217585 0

Some information from your script:

   5  Model Identifier: iMac17,1

   6  Boot ROM Version: IM171.0105.B07

   7  System Version: OS X 10.11.4 (15E65)

   8  Kernel Version: Darwin 15.4.0

   9  Time since boot: 46 minutes

  57  Shutdown codes

  58 

  59      -128 9

Didn't find anything that seems relevant to the reboot at 4/9/16 8:59:45.000 AM.  Like Terry, I believe this is a hardware/firmware issue, most likely due to the recent update.  I guess I'll just have to wait and see if a fix will be available soon.

Hi guys, am so pleased to have found someone with the same issue I thought it was just me.

Mine does the same thing, ever since the update.

It also sometimes boots with bluetooth disabled completely, only solvable by restarting the iMac, which is pretty lame to have to do it every time i turn it on.

Re paring, deleting the plist and resetting the SMC (as advised by apple online support) made no difference except the first time i tired to reset the SMC it solved the bluetooth problem , but it was only temporary as after about 3 days it just went back to doing the same. Random restarts and booting with no bluetooth.

Im almost convinced it was perfect before the update but i cannot be sure as i didn't use my iMac for 2 - 3 weeks after buying it so it was only on a few days before the update but if my memory is correct it didn't have any problem at all when first unboxed and booted.

This is only supposed to happen to windows machines lol

Hope someone can help

Thanks in advance.

Mine also is restarting randomly after updating to 10.4. No problems the first 45 days.  Been on the line with Apple and the case has been escalated to the highest level. Restarts at least once per day. About 20 seconds before a restart mouse freezes and then it does a rapid restart. System log first indicated PogoPlugPc. Removed App and computer was stable for 4 days - no restarts. Then it started restarting again. System log pointed to airplayxpchelper trying to log onto an IP address. Force Quit AirPlayxpchelper and computer went a whole day before restarting. Now a new App is the last thing showing before a restart.

Seems to be random Apps causing the issue. I sent my log file to Apple and they are supposed to get back to me by May 13th. My IMac is less than 3 months old and I dumped two grand into this machine and I am not happy. I asked about a replacement computer but haven't gotten that far yet - first they would like to solve the issue.  Just afraid all late 2015 5K Macs have this issue.

It actually restarted while I was on the phone with the Tech Supervisor. She was very surprised by this issue and has been following this thread now.

It's frustrating the life out of me.

After numerous calls and reinstall apple support recommended I take it to a service center and go from there.

Will be taking it in on Monday so I'll post if there is any solution or if I end up getting a new machine I'll let you guys know.

Did you have any luck with your machine?

I'm on the same page,  after paying nearly 2k for it I expect it to work properly.

Mine is less than 3 months old. I just e-mailed the supervisor requesting an RMA sticker and asking for a NEW replacement computer. In my industry (Swimming Pool Equipment) we do this all the time during the one year Warranty period. No sense having a customer try to repair a product that is obviously defective - just simply swap it out. Apple doesn't seem to want to work it that way...

Their last "guess" was that it was the RAM. I purchased 5K compatible RAM and removed the factory RAM and replaced it. Still restarts at least twice a day now even with the new RAM - so it is not the RAM.

They do not have any idea what the problem is. I can tell you what it is - a defective product line. Three years ago every single pool motor from Pentair would fail within 6 months. A whole batch of pool motors with bad windings. It happens, and Apple needs to step up and exchange these computers for us. Have owned computers since RGB Monitors and Dot Matrix printers and never had one randomly restarting on me - certainly not without any crash report or error message. Certainly not multiple times a day. It's a lemon.

Hate to be the me too guy but I too have a month old iMac (Retina 5K, 27, late 2015, 4 ghz i7, 16 gb 1867 mhm ddr3, and radeon r9 m395 2048 mb, 500 GB of flash) and about 2-3 times a day the cursor freezes, keyboard stops working (both bluetooth of course), after about a minute it restarts. I can't really use it for productivity because I can't predict when it will happen. So I paid well over 3 grand to surf the internet. Thank goodness my MBPro is avail for work. I will take this back to the Apple Store as soon as school gets out (2 hrs away.) Come on Apple step up and fix this. I miss Steve.

Same issues as everyone else: Freezing while using (mail and safarI0 and while not using iMac late 2015. No problems with 10.11.3 until I updated to 10.11.4 and got the freezes/random reboots. Went back to 10.11.3 via Time Machine backup but freezes/restarts continued. Did everything anyone ever suggested about the problem (disabled plug-ins, extensions, Apple Diagnostics, Disk Utility First Aid, turned off Web Gl, turned off automatic backups, and more). Never get any error messages just freeze and restart with chimes. Did EtreCheck but no issues found. So updated to 10.11.5 via combo update...STILL HAVING FREEZES/RESTARTS.  Will call Apple today but not hopeful given what everyone else is experiencing. I live 160 miles away from the nearest Apple repair so hope it's not hardware. Thanks for all the information everyone is giving.

Just called Apple and "we" reset the SMC and am now waiting 30 minutes and they will call back but I am dubious because often nothing happens for several hours.

I updated to 10.11.5 four days ago. It restarted once the first day after updating but for 3 days now it has not restarted. I can't get my hopes up too high since it has been stable for up to four days prior and then did the random restarts again twice a day.  Apple still has not follow-up in about 10 days - they are still researching the logs I sent them...

Since updating to 10.11.5 my computer has stayed on for 5 days now - a new record without restarting. I am hopeful...

Reboots have not stopped with 10.11.5. Fewer, but they still happen. Taking iMac purchased in April back to Apple Store. Sad.

I've had my Imac on for 6 days now and no restarts with the 10.11.5 - I had also removed the factory memory before the update and I am running it with this memory:

Adamanta 16GB (2x8GB) Apple Memory Upgrade for Late 2015 iMac 27" DDR3 1867Mhz PC3-14900 SODIMM 2Rx8 CL13 1.35v RAM

The engineers who looked at the log said it was RAM related.  So maybe it is the RAM conflicting with the 10.11.4 update and still in conflict with the 10.11.5 but not as badly. My machine did not restart for two months - only after I updated to 10.11.4 - it would restart at least twice a day. It seems to be the OS in conflict with the Hardware.

最後更新：2017-09-04 13:57:58

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