VBBob
Level 1 (4 points)
Desktops

Q: I have a late 2009 era 27"-iMac running OS X 10.9.5 with a display issue.  Looking for some guidance.

I have a late 2009 era 27"-iMac running OS X 10.9.5.  The normal boot process never completes and the display is gray with wide vertical noise bands that sometimes change colors and are about 1-1/4" wide.  Sometimes there is a uniform distribution of small noise blotches (about 1/4" square) that appear (like "snow") over the entire screen, with or without the vertical bands. 

 

Booting in "Safe" mode allows the boot process to complete and a normal desktop to appear, although frequently there is some of the display problem (the bands and/or "snow").  When working in this mode, the display noise clears up with use (e.g., dragging a window across the noise), but reappears on a continual basis.  Today I was able to boot using safe mode and have none of the display problems, but that is a first.

 

Any insights into what is the likely cause?  Nothing is connected to the iMac other than the USB keyboard and a wireless Apple mouse.

 

Is it worth the likely cost to repair this problem on a nearly 7-year old iMac?

 

Background:  This iMac is used exclusively by my wife for email and internet browsing, plus an occasional use of Pages.  I'm using an iMac that is nearly 3 years old and will likely replace it with a new iMac within the year which will allow us to replace the problem iMac with the newer one I'm currently using.

iMac, Product and OS identified

Posted on Aug 2, 2016 6:24 AM

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VBBob

Q: I have a late 2009 era 27"-iMac running OS X 10.9.5 with a display issue.  Looking for some guidance.

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  • by Eric~F,Helpful

    Eric~F Eric~F Aug 3, 2016 11:56 AM in response to VBBob
    Community Specialists
    Aug 3, 2016 11:56 AM in response to VBBob

    Hello VBBob,

     

    Thanks for asking your question here in the Apple Support Communities. Thanks for describing your issue in such detail also. Sounds like you are experiencing an issue with the software. Since the boot process completes in safe mode, it tells us that the issue is related to a startup item or plugins because safe mode disables 3rd party drivers and forces Apple only drivers to operate. Also safe mode may present those issues with the screen because the Mac runs slower in safe mode, and may also have a “glitchy” looking screen.

     

    I first want to recommend that you boot into safe mode and make a full backup of all your data. All you need is an external hard drive. This help article from Apple will help you make the backups: Use Time Machine to back up or restore your Mac

     

    Once you know your data is safe, you want to try disabling any login items that automatically open when you log in. This info comes from this article: Try safe mode if your Mac doesn‘t finish starting up in the section titled "If an issue doesn't happen in safe mode". It leads you to this article to assist you: OS X Yosemite: If you think you have incompatible login items. The steps are the same for Mavericks and Yosemite.

     

    You may also want to test this in a test user which will let us know if the issue is isolated to your account, or system wide. This article from Apple will help: How to test an issue in another user account on your Mac. If you make a new user in safe mode and can boot into it normally (restart the Mac and then try to log in to the test user), then check the area in that article titled: "If an issue happens in only one user account" which leads to Mac OS X: How to troubleshoot a software issue.

     

    Thanks again and have a great rest of your day.

  • by VBBob,

    VBBob VBBob Aug 3, 2016 12:02 PM in response to Eric~F
    Level 1 (4 points)
    Desktops
    Aug 3, 2016 12:02 PM in response to Eric~F

    Thank you, Eric-F,

     

    The iMac in question has two users already and so I don't have to check whether the issue is confined to one user.

     

    I will check the start-up items and see if there is something there.

     

    This is good information and I'm thankful to have it.

     

    I'll get back after I've tried the suggestions.  I do have Time Machine and might first try to restore the system to a date prior to when the problem began.  I'll need to boot in safe mode and then see if I can connect the Time Machine drive from which I can do a restore... I'm sure the information you've provided will be quite helpful.

  • by rkaufmann87,

    rkaufmann87 rkaufmann87 Aug 3, 2016 12:36 PM in response to VBBob
    Level 9 (58,184 points)
    Photos for Mac
    Aug 3, 2016 12:36 PM in response to VBBob

    If you post an EtreCheck report, it will list the plugins you have installed. You can begin by either updating or removing them one by one until you find the offending plugin. If you are not familiar with EtreCheck, Google it, then download and run the report. Look in the plugins section and begin testing.

  • by VBBob,

    VBBob VBBob Aug 4, 2016 9:02 AM in response to rkaufmann87
    Level 1 (4 points)
    Desktops
    Aug 4, 2016 9:02 AM in response to rkaufmann87

    The information was helpful (EtreCheck) and it did flag the startup items that were all obsolete.  I removed them and was able to boot normally, however, the problem returned.

     

    I've put information on my Dropbox account that contains a whole screen capture of one of the manifestations of the problem:

     

    Link:  https://www.dropbox.com/sh/h8agssv62mrz6sc/AABzuLr4jJDLz_8EoWzR36ZTa?dl=0

     

    Look at screen-capture.jpg to see the vertical banding.  Also, the dialog box relating to Apple TV appeared for no apparent reason.

     

    I used a terminal session to see if the problem would show up in the session window.  It did not and I was able to "erase" any noise from the desktop outside the terminal session window by dragging the window around the desktop as if it were an eraser!

     

    So I'm able to sometimes boot normally.  But when that fails to complete (usually because the video problem appears), then I can always boot in Safe Mode.

     

    When I am able to get a normal boot, if I walk away from the screen for 20 or 30 minutes, several times I've come back to find the desktop reduced in size and the entire screen covered with a uniform distribution of small square patches of video noise.  Also, the gray line a the top of the desktop is missing and nothing can be done (the iMac is locked) other than pressing the power button to shut down.  After such a failure, I have to boot in Safe mode before I can succeed with a normal boot.

     

    If a normal boot starts to exhibit the video noise (particularly the noise patches covering the entire screen) before the boot is finished, it will fail and I'll have to press the power button to shut down.

     

    I'm beginning to suspect a hardware issue that is triggered by use or time powered up (or both) before the failure is manifested.  However, because Safe boot has always worked, there may be something triggering the problem that can be fixed, though there are no startup items in the Library now.

  • by rkaufmann87,

    rkaufmann87 rkaufmann87 Aug 4, 2016 9:03 AM in response to VBBob
    Level 9 (58,184 points)
    Photos for Mac
    Aug 4, 2016 9:03 AM in response to VBBob

    Please post your EtreCheck report and we can look for other obvious issues.

  • by VBBob,

    VBBob VBBob Aug 4, 2016 11:40 AM in response to rkaufmann87
    Level 1 (4 points)
    Desktops
    Aug 4, 2016 11:40 AM in response to rkaufmann87

    https://www.dropbox.com/s/p6pnnuzogpjo3z3/EtreCheck.pdf?dl=0

     

    ... dropbox link to EtreCheck.pdf containing the EtreCheck report.

  • by VBBob,

    VBBob VBBob Aug 4, 2016 11:42 AM in response to rkaufmann87
    Level 1 (4 points)
    Desktops
    Aug 4, 2016 11:42 AM in response to rkaufmann87

    Some of the report (right side of page) was truncated... didn't realize it until I'd posted the link.

     

    If you need the full material for those areas truncated, let me know and I'll run it again.

  • by rkaufmann87,

    rkaufmann87 rkaufmann87 Aug 4, 2016 12:02 PM in response to VBBob
    Level 9 (58,184 points)
    Photos for Mac
    Aug 4, 2016 12:02 PM in response to VBBob

    We need to see the complete report please.

  • by VBBob,

    VBBob VBBob Aug 4, 2016 12:34 PM in response to rkaufmann87
    Level 1 (4 points)
    Desktops
    Aug 4, 2016 12:34 PM in response to rkaufmann87

    I'll rerun it, but cannot do that until this evening.  I'll post it when it's available.

     

    I'm not working on the problem iMac and it is a bit tricky to run the program and save the report to a file so that I can transfer it to a portable drive to put on my working iMac and then post it at dropbox.

  • by rkaufmann87,Helpful

    rkaufmann87 rkaufmann87 Aug 19, 2016 2:42 PM in response to VBBob
    Level 9 (58,184 points)
    Photos for Mac
    Aug 19, 2016 2:42 PM in response to VBBob

    All you do is run the report on the computer and then copy and paste the results to your reply to this message. No need to do ANYTHING else.

  • by VBBob,

    VBBob VBBob Aug 4, 2016 4:28 PM in response to rkaufmann87
    Level 1 (4 points)
    Desktops
    Aug 4, 2016 4:28 PM in response to rkaufmann87

    The complete report in pdf format is in the folder at:

     

    https://www.dropbox.com/sh/h8agssv62mrz6sc/AABzuLr4jJDLz_8EoWzR36ZTa?dl=0

     

    One flagged area that may be helpful:

     

    System Launch Daemons: i

         [failed] com.apple.ucupdate.plist

         [not loaded] 49 Apple tasks

         [loaded] 136 Apple tasks

         [running] 63 Apple tasks


    I've also made a pdf of the failed com.apple.ucupdate.plist and put it in the same folder (as com.apple.ucupdate.plist.pdf)


    I hope this is helpful.  Let me know if there is anything else I should try.


    Thanks for your help...

     

  • by VBBob,

    VBBob VBBob Aug 4, 2016 4:56 PM in response to rkaufmann87
    Level 1 (4 points)
    Desktops
    Aug 4, 2016 4:56 PM in response to rkaufmann87

    Here is the com.apple.ucupdate.plist file contents:

     

    <?xml version="1.0" encoding="UTF-8"?>

    <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">

    <plist version="1.0">

    <dict>

              <key>Label</key>

              <string>com.apple.ucupdate.plist</string>    

              <key>RunAtLoad</key>

              <true/>

              <key>ProgramArguments</key>

              <array>

                        <string>/usr/libexec/ucupdate</string>         

                        <string>-m</string>    

                        <string>/usr/share/ucupdate/microcode.dat</string>

              </array>

    </dict>

    </plist>

  • by VBBob,

    VBBob VBBob Aug 19, 2016 2:45 PM in response to VBBob
    Level 1 (4 points)
    Desktops
    Aug 19, 2016 2:45 PM in response to VBBob

    Just wanted to note for the record that the problem was resolved without the need for hardware service.

     

    I followed instructions and deleted any obsolete/unused plist files, restarted and the iMac has been working flawlessly ever since.

     

    Strangest problem I've ever encountered with a Mac.

     

    Thanks to all who helped with comments & suggestions.