7 Replies Latest reply: Oct 22, 2013 2:17 AM by PlotinusVeritas
miss miso Level 1 (0 points)

Hi there,


This is my first time posting so thanks for your assistance!


Last night I was in the middle of watching a tv show  on my laptop via my external hard drive (WD 3200BMV) when my friend called so I paused the show. The hard drive cable got knocked and unmounted without being ejected. This has happened before and it has rectified itself so I didn't worry. When I got off the phone and went to resume watching it wouldn't read the file. I assumed that I needed to eject the drive and start again but it wouldn't eject so I forced eject and then restarted my computer. When I plugged the drive back in it came up in Finder with the files listed, but I couldn't open any of the files. (The files are selected to read/write)


The plot thickens! I decided to see if the drive would work on my housemate's PC, which it did (I could access and open the files). I called Apple Support for some advice and the technician suggested I plug in a usb stick and other hard drives to my mac to see if they would work. My usb stick worked fine and so did my iphone, but my Seagate ext hard drive which I use for time machine would not come up.


When I go to Disk Utility the WD drive is showing (but I cannot verify or repair disk - "some information was unavailable during an internal look up) but the Seagate drive doesn't come up at all. Also, the light on the Seagate drive goes on and off when I move it slightly.


This is very confusing! The Apple Support tech said I should book an appointment at an Apple store, and also said this:


"Also, with the external hard drive, make sure to back up the data to another computer, then you can reformat the hard drive. There's likely nothing wrong with it, just the file formats were changed when it was force-edjected from the usb port."


That would make sense to me if I wasn't having an issue with the Time Machine Drive also!


Any assistance would be most appreciated. I am happy to give more information if needed. Cheers

MacBook Pro, Mac OS X (10.7.5)
  • PlotinusVeritas Level 6 (14,725 points)

    youve confused your information a bit.


    you have 2 external HD ....WD and seagate .......yes?


    which one got knocked out?


    which HD is not showing at ALL in disk utility?





    Youve got a broken chain of causation.......youre blaming your WD being knocked around for your Seagate "not showing up in DU"


    "but my Seagate ext hard drive which I use for time machine would not come up."


    The two are unrelated obviously.



    Verify your Seagate on another Mac, if it doesnt show up, the SATA bridge card is bad, which is VERY common in fact.



  • miss miso Level 1 (0 points)

    Hi Plotinus,


    Thanks for your reply. Sorry if I was unclear.


    My WD drive got knocked out.


    My Seagate drive does come up on another Mac, and my WD drive shows up on my friend's PC.


    But I can't access them properly on my Mac.


    WD drive is formatted to FAT32 I believe (if that is relevant)


    Seagate (Time Machine back-up) is not showing up in Disk Utility.



  • PlotinusVeritas Level 6 (14,725 points)

    Wiggling on USB port causes the seagate to appear


    Reason the stick came up is it doesn't put and pressure on the USB port



    All current info points at a bad USB port.



    lastly confirm both HD on both USB ports.    Specifically the other USB port

  • miss miso Level 1 (0 points)

    Thanks for getting back to me.


    FYI, I took my mac and the drives to a technician a friend recommended and it became clear that the Seagate drive was faulty, so we replaced the case and now it works fine. Still had issues with opening the files on the WD drive. He is going to try copying the data from my WD drive onto his computer and then re-formatting my drive and copying the files back. Hopefully it will all work after that.


    Thanks again for your help!

  • PlotinusVeritas Level 6 (14,725 points)

    ahh, so it was the part i warn people about... the SATA bridge card is bad, VERY common problem



    Another dead SATA card



    You replaced the case, that didn't mean the HD was bad just that card,.....good news

  • miss miso Level 1 (0 points)

    Yes, good news!

  • PlotinusVeritas Level 6 (14,725 points)

    You said---Seagate drive was faulty, so we replaced the case


    Well, its enclosure with SATA card was faulty, not the HD itself.



    Ive heard about failing SATA cards so much over many years, I decided to write USER TIP on it.


    Alas its so common a problem. 


    Your dead external hard drive is likely fine! Great hope for your 'faulty' external HD



    There are no hard facts whatsoever, especially since so many people discard their assumed “dead/faulty” hard drives, but a good educated conclusion from years of examining and seeing this issue is that for hard drives made since 2010, and not dropped or generally abused, is that a minimum of 50% conservatively are perfectly fine! I personally estimate however that it likely approaches 60%+.