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iMac 21.5 inch frequent system crashes

1485 Views 22 Replies Latest reply: Sep 4, 2013 12:30 PM by MadMacs0 RSS
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Ethanace Level 1 Level 1 (0 points)
Currently Being Moderated
May 23, 2013 8:08 AM

In the last month I have noticed a series of sudden computer freeze-ups (like you'd expect on Windows) happening on my Mac when using Safari. The computer is under little to no stress when the freeze occurs, and it's almost always when opening a new tab on Safari, or clicking a link, and then the whole system seizes up. This has never happened in the past but it's happened now 4 times in the past month and I am starting to get worried. I do not pirate any software, and I have a genuine ESET NOD32 antivirus installed and running; I conducted a scan the same day of a crash and it found nothing after a full 4-hour in-depth scan. I'm now wondering if this is a software bug in Safari, or if this could be hardware related...


Is there anywhere in the system I can view event logs, such as Event Viewer on Windows? I want to try and diagnose what the issue is by reading any log I can find. Is there also an application that can determine the cause of a crash that can run in the background while I work?




iMac 21.5"


Late 2009


3.06GHz Intel Core 2 Duo

4GB DDR3 RAM 1066MHz

1TB Hitachi HDD

256MB ATI Radeon HD 4670


Mountain Lion 10.8.3

Safari 6.0.4 (I believe this issue also happened with 6.0.3)


Any advice would be greatly appreciated, thanks.

iMac, OS X Mountain Lion
  • Baby Boomer (USofA) Level 9 Level 9 (55,540 points)
    Currently Being Moderated
    May 23, 2013 10:15 AM (in response to Ethanace)

    I have a genuine ESET NOD32 antivirus installed and running;


    Uninstall it.  Mac OSX do not get viruses therefore it is not needed.  If the crashing stops, you will know that the antivirus was the culprit.  If the crashing continues, suggest that you post in the Safari forum as that is where its users hang out.













  • Rudegar Level 6 Level 6 (18,480 points)
    Currently Being Moderated
    May 23, 2013 11:18 AM (in response to Ethanace)

    look for logs in




  • Linc Davis Level 10 Level 10 (107,810 points)
    Currently Being Moderated
    May 23, 2013 2:35 PM (in response to Ethanace)

    Uninstall ESET by following the instructions on this page:

    If you have a different version of the product, the procedure may be different. Back up all data before making any changes.

  • Baby Boomer (USofA) Level 9 Level 9 (55,540 points)
    Currently Being Moderated
    May 24, 2013 3:23 PM (in response to Ethanace)

    Ethanace wrote:


    I am reluctant to uninstall ESET NOD32 as I have paid for it; also it's a well-known extremely good antivirus that uses very little system recourses. I know it is not the cause of the crashing as it has been installed on my system since late last year and the crashing has only started in the past 4 weeks.


    Also, to say that Mac users do not get viruses is a myth; and one that should be stamped out fairly quickly. You can get viruses on a Mac, and it will become increasingly common as Apple continues to gain marketshare in the computer industry. It is extremely unlikely unless you are downloading illegal software - but the point is it can happen and I cannot tolerate the possibility of a virus under any circumstances.


    I stated OSX does not get viruses.  It's a fact, not a myth.


    Check out User Tip:   Viruses, Trojans, Malware - and other aspects of Internet Security and Mac Malware Guide.





    Are programs that earn their name by their ability to replicate themselves locally & often across a network.  Many attach themselves to to other programs.  When you launch one of these programs, the virus code launches as well & the virus goes about its nefarious business.

    Viruses are exceedingly rare on the Mac.  There are no known viruses for OSX.



    Promises one thing but delivers another.  You can download a program but when you run the program, the contents of your computer are instead beamed to an underground data center in Kamchatka.  If you obtain software from reliable sites, you are unlikely to get a Trojan horse.



    Has an embedded advertising component - one that displays or downloads ads when you run the software.  Some adware is legitimate, part of the price of using a free program such as the Iconfactory's Twitterrific or Eudora for example.



    Grabs data from your computer & ofen uses it for the purposes of evil, sending personal info to a baddie or when you're using your web browser, redirecting you to site you don't want to visit.


    Mac users have nothing to worry about regarding Spyware & Adware because in order for the worse forms to work, the OS must allow unrestricted access to its more sensitive parts.  The Mac OS doesn't.












    iMac (3.2 GHz, Intel Core i5-2013), OS X Mountain Lion (10.8.3), Fusion Drive-3.12TB, 32GB RAM
  • Linc Davis Level 10 Level 10 (107,810 points)
    Currently Being Moderated
    May 24, 2013 3:51 PM (in response to Ethanace)

    First, the fact that you paid for ESET doesn't alter the fact that it's worthless and will never do anything but slow down and destabilize your system. It will never protect you from malware.


    I suggested you uninstall ESET and test. You can reinstall it easily if there's no improvement. If you're not willing to carry out that test, I have no other suggestions.

  • Linc Davis Level 10 Level 10 (107,810 points)
    Currently Being Moderated
    May 24, 2013 3:52 PM (in response to Ethanace)

    1. This comment applies to malicious software ("malware") that's installed unwittingly by the victim of a network attack. It does not apply to software, such as keystroke loggers, that may be installed deliberately by an intruder who has hands-on access to the victim's computer. That threat is in a different category, and there's no easy way to defend against it. If you have reason to suspect that you're the target of such an attack, you need expert help.
    OS X now implements three layers of built-in protection specifically against malware, not counting runtime protections such as execute disable, sandboxing, system library randomization, and address space layout randomization that may also guard against other kinds of exploits.

    2. All versions of OS X since 10.6.7 have been able to detect known Mac malware in downloaded files, and to block insecure web plugins. This feature is transparent to the user, but internally Apple calls it "XProtect." The malware recognition database is automatically checked for updates once a day; however, you shouldn't rely on it, because the attackers are always at least a day ahead of the defenders.
    The following caveats apply to XProtect:
    • It can be bypassed by some third-party networking software, such as BitTorrent clients and Java applets.
    • It only applies to software downloaded from the network. Software installed from a CD or other media is not checked.
    3. Starting with OS X 10.7.5, there has been a second layer of built-in malware protection, designated "Gatekeeper" by Apple. By default, applications and Installer packages downloaded from the network will only run if they're digitally signed by a developer with a certificate issued by Apple. Software certified in this way hasn't necessarily been tested by Apple, but you can be reasonably sure that it hasn't been modified by anyone other than the developer. His identity is known to Apple, so he could be held legally responsible if he distributed malware. That may not mean much if the developer lives in a country with a weak legal system (see below.)
    Gatekeeper doesn't depend on a database of known malware. It has, however, the same limitations as XProtect, and in addition the following:
    • It can easily be disabled or overridden by the user.
    • A malware attacker could get control of a code-signing certificate under false pretenses, or could simply ignore the consequences of distributing codesigned malware.
    • An App Store developer could find a way to bypass Apple's oversight, or the oversight could fail due to human error.
    For the reasons given above, App Store products, and other applications recognized by Gatekeeper as signed, are safer than others, but they can't be considered absolutely safe. "Sandboxed" applications may prompt for access to private data, such as your contacts, or for access to the network. Think before granting that access. OS X security is based on user input. Never click through any request for authorization without thinking.
    4. Starting with OS X 10.8.3, a third layer of protection has been added: a "Malware Removal Tool" (MRT). MRT runs automatically in the background when you update the OS. It checks for, and removes, malware that may have evaded the other protections via a Java exploit (see below.) MRT also runs when you install or update the Apple-supplied Java runtime (but not the Oracle runtime.) Like XProtect, MRT is presumably effective against known attacks, but maybe not against unknown attacks. It notifies you if it finds malware, but otherwise there's no user interface to MRT.
    5. XProtect, Gatekeeper, and MRT reduce the risk of malware attack, but they're not absolute protection. The first and best line of defense is always your own intelligence. With the possible exception of Java exploits, all known malware circulating on the Internet that affects a fully-updated installation of OS X 10.6 or later takes the form of so-called "trojan horses," which can only have an effect if the victim is duped into running them. The threat therefore amounts to a battle of wits between you and the malware attacker. If you're smarter than he thinks you are, you'll win.
    That means, in practice, that you never use software that comes from an untrustworthy source, or that does something inherently untrustworthy. How do you know what is trustworthy?
    • Any website that prompts you to install a “codec,” “plug-in,” "player," "extractor," or “certificate” that comes from that same site, or an unknown one, is untrustworthy.
    • A web operator who tells you that you have a “virus,” or that anything else is wrong with your computer, or that you have won a prize in a contest you never entered, is trying to commit a crime with you as the victim. (Some reputable websites did legitimately warn visitors who were infected with the "DNSChanger" malware. That exception to this rule no longer applies.)
    • Pirated copies or "cracks" of commercial software, no matter where they come from, are unsafe.
    • Software of any kind downloaded from a BitTorrent or from a Usenet binary newsgroup is unsafe.
    • Software that purports to help you do something that's illegal or that infringes copyright, such as saving streamed audio or video for reuse without permission, is unsafe. All YouTube "downloaders" are in this category, though not all are necessarily harmful.
    • Software with a corporate brand, such as Adobe Flash Player, must be downloaded directly from the developer’s website. If it comes from any other source, it's unsafe.
    • Even signed applications, no matter what the source, should not be trusted if they do something unexpected, such as asking for permission to access your contacts, your location, or the Internet for no obvious reason.
    6. Java on the Web (not to be confused with JavaScript, to which it's not related, despite the similarity of the names) is a weak point in the security of any system. Java is, among other things, a platform for running complex applications in a web page, on the client. That was always a bad idea, and Java's developers have proven themselves incapable of implementing it without also creating a portal for malware to enter. Past Java exploits are the closest thing there has ever been to a Windows-style virus affecting OS X. Merely loading a page with malicious Java content could be harmful.
    Fortunately, client-side Java on the Web is obsolete and mostly extinct. Only a few outmoded sites still use it. Try to hasten the process of extinction by avoiding those sites, if you have a choice. Forget about playing games or other non-essential uses of Java.
    Java is not included in OS X 10.7 and later. Discrete Java installers are distributed by Apple and by Oracle (the developer of Java.) Don't use either one unless you need it. Most people don't. If Java is installed, disable itnot JavaScript — in your browsers.
    Regardless of version, experience has shown that Java on the Web can't be trusted. If you must use a Java applet for a task on a specific site, enable Java only for that site in Safari. Never enable Java for a public website that carries third-party advertising. Use it only on well-known, login-protected, secure websites without ads. In Safari 6 or later, you'll see a lock icon in the address bar with the abbreviation "https" when visiting a secure site.

    Follow the above guidelines, and you’ll be as safe from malware as you can practically be. The rest of this comment concerns what you should not do to protect yourself from malware.

    7. Never install any commercial "anti-virus" or "Internet security" products for the Mac, as they all do more harm than good, if they do any good at all. Any database of known threats is always going to be out of date. Most of the danger is from unknown threats. If you need to be able to detect Windows malware in your files, use the free software  ClamXav— nothing else.
    Why shouldn't you use commercial "anti-virus" products?
    • Their design is predicated on the nonexistent threat that malware may be injected at any time, anywhere in the file system. Malware is downloaded from the network; it doesn't materialize from nowhere.
    • In order to meet that nonexistent threat, the software modifies or duplicates low-level functions of the operating system, which is a waste of resources and a common cause of instability, bugs, and poor performance.
    • By modifying the operating system, the software itself may create weaknesses that could be exploited by malware attackers.
    8. ClamXav doesn't have these drawbacks. That doesn't mean it's entirely safe. It may report email messages that have "phishing" links in the body, or Windows malware in attachments, as infected files, and offer to delete or move them. Doing so will corrupt the Mail database. The messages should be deleted from within the Mail application.
    ClamXav is not needed, and should not be relied upon, for protection against OS X malware. It's useful only for detecting Windows malware. Windows malware can't harm you directly (unless, of course, you use Windows.) Just don't pass it on to anyone else.
    A Windows malware attachment in email is usually easy to recognize. The file name will often be targeted at people who aren't very bright; for example:
    ClamXav may be able to tell you which particular virus or trojan it is, but do you care? In practice, there's seldom a reason to use ClamXav unless a network administrator requires you to run an anti-virus application.
    9. The greatest harm done by security software, in my opinion, is in its effect on human behavior. It does little or nothing to protect people from emerging threats, but if they get a false sense of security from it, they may feel free to do things that expose them to higher risk. Nothing can lessen the need for safe computing practices.
    10. It seems to be a common belief that the built-in Application Firewall acts as a barrier to infection, or prevents malware from functioning. It does neither. It blocks inbound connections to certain network services you're running, such as file sharing. It's disabled by default and you should leave it that way if you're behind a router on a private home or office network. Activate it only when you're on an untrusted network, for instance a public Wi-Fi hotspot, where you don't want to provide services. Disable any services you don't use in the Sharing preference pane. All are disabled by default.

  • MadMacs0 Level 4 Level 4 (3,320 points)
    Currently Being Moderated
    May 24, 2013 5:07 PM (in response to Ethanace)

    Ethanace wrote:


    I know it is not the cause of the crashing as it has been installed on my system since late last year and the crashing has only started in the past 4 weeks.

    I'm sorry, but without seeing at least a crash log, I don't see how you can discount anything as the cause. You also haven't told us what changed four weeks ago, so we can't even provide you with a guess.

    Also, to say that Mac users do not get viruses is a myth; and one that should be stamped out fairly quickly. You can get viruses on a Mac, and it will become increasingly common as Apple continues to gain marketshare in the computer industry. It is extremely unlikely unless you are downloading illegal software - but the point is it can happen and I cannot tolerate the possibility of a virus under any circumstances.

    There are some technical issues with what you have said, but I can agree with a small part of it. As Apple continues to gain market share, it will be targeted more often. If you substitute the word "malware" for "viruses", I'd agree with even more. But there has not been an occurrence of malware that can spread all by itself in many years, nor do I expect there to be. Malware isn't about hacking for fun or even illegal software any more, it's now where the money is. Most malware is simply designed to force you to look at advertising, which is certainly a nuisance and can significantly interrupt your computer routine, especially when poorly written. But it's now mainstream, with lots of drive-by Java infections from hundreds of main stream blog sites that are suddenly infected and enough tweaking to defeat the best of the A-V scanners. Almost all malware is now zero-day, meaning that it takes two or three days of mass infection before all the A-V vendors can catch up with it. You may be one of the lucky ones that ESET catches early, but odds are that won't happen to those with an early infection. I have a lot of confidence in OS X, especially Mountain Lion's protection as long as you keep it fully up-to-date and don't turn off or ignore what's there. Virtually all A-V software provides some degree of additional protection, but none have reached perfection, so the only way you can possibly mean your goal of zero infections is to stay off the Internet completely and not plug in an external source that came from somewhere else.

  • Paul_31 Level 6 Level 6 (12,195 points)
    Currently Being Moderated
    May 25, 2013 12:22 PM (in response to Ethanace)

    It seems strange that you posted your issue seeking help, yet you don't seem prepared to at least consider the advice that has been given as a possible solution. It would cost nothing to follow the suggestions offered and it just may help. If it doesn't resolve things, re-install it and look for other solutions.

    The fact it's worked fine for the last six months should be discounted as it's possible that some other update or software installation has 'rocked the boat' and caused this new development.

    Obviously it's your choice as to what you do in trying to resolve the problem.

  • MadMacs0 Level 4 Level 4 (3,320 points)
    Currently Being Moderated
    May 25, 2013 12:42 PM (in response to Ethanace)

    I don't see how arguing about A-V software is helping you diagnose your problem.


    Can you please just post a crash report and/or an EtreCheck so we can see what else you have going on?

  • Paul_31 Level 6 Level 6 (12,195 points)
    Currently Being Moderated
    May 25, 2013 12:47 PM (in response to Ethanace)

    I appreciate your concerns about security and protecting your Mac, but I don't think you'd be running a risk so long as you keep your Mac up-to-date; disable Java in all browsers - or only enable it when required and also ensure Flash is current. In fact, OS X will disable them anyway if any known threats occur.

    But if you still want to have an anti-virus program running, the free/donationware clamXav is the one that is consistently recommended as 'works well with Macs':

  • John Galt Level 7 Level 7 (33,085 points)
    Currently Being Moderated
    May 25, 2013 4:49 PM (in response to Ethanace)

    I am very cautious of feeling vulnerable for so long.


    Feeling vulnerable, or not, is not relevant. Adherence to practices that actually enhance security, and "feeling good" by relying upon some third party junk that claims to protect OS X better than the engineers who designed and maintain it are unrelated concepts. Eset and all similar rubbish will accomplish one and not the other.


    Eset has already wasted your money and is now wasting your time. OS X already includes everything it requires to protect itself from viruses and malware.


    See this post: Why is my macbook so laggy all of a sudden? That report belies your claim that eset "uses very little system recourses (sic)" and suggests it is the likely cause of your problems.

    Any advice would be greatly appreciated, thanks.

    It appears that is not the case. Several experienced Mac users provided sound advice that you have chosen to ignore. I expect you will ignore mine as well, so good luck.

    MacBooks  iMacs  iPads  AirPorts, OS X Mountain Lion,  28 years Apple!
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