External hard drives not recognized by imac

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External hard drives not recognized by imac

I am a new Mac user and have been having lots of trouble getting my external hard drives to mount. I have a simpletech and a seagate external hard drive both NFTS formatted neither of which is recognized by my iMac. They don't show up on disk utility or system profiier under USB ports. They both work on my PC laptop and a friends iMac (OS 10.6.4) just fine. I have a card reader and flash drive that work perfectly on my iMac. Apple support orginally thought it might be the logic board so they replaced it. The new one is having the exact same problem. Does anyone have any idea what could possibly be the problem?? This is driving me insane.

iMac, Mac OS X (10.6.4)

Posted on Sep 1, 2010 1:46 PM

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Answer 1

techfan

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Sep 1, 2010 2:34 PM in response to teethdr

I'm having exactly the same problem with a new iMac purchased one week ago. I have two Maxtor drives and one WD, all firewire 400 drives, all of which mount briefly and then unmount and will not mount again. I am not new to Macs. The drives work fine on the older PowerPC Mac running 10.4.11. These drives contain my backups and aren't recognized by the new iMac. I cannot believe that 3 external drives are all going into failure mode at the same time since they were all purchased at different times and only used as backup drives, so they weren't on all of the time. Is there an incompatibility between 800 and 400?? I'm using a LaCie 800 to 400 firewire cable. Suggestions??

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Answer 2

rkaufmann87

Level 10

143,850 points

Sep 1, 2010 2:44 PM in response to teethdr

OSX doesn't natively work with NFTS. What you need to do is download and install NTFS-3G and your problems should be solved. Of course after installing it restart the computer.

Regards,

Roger

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Answer 3

teethdr Author

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Sep 1, 2010 8:13 PM in response to rkaufmann87

Thanks for the help. I was really hopeful this would work since I have spent countless hours googling and with Apple support. I downloaded Tuxera NFTS-3G and restarted but my hard drives will still not mount or even be recognized for that matter.

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Answer 4

rkaufmann87

Level 10

143,850 points

Sep 1, 2010 8:24 PM in response to teethdr

Well I'm a little taken aback that it didn't work. The next thing I'd recommend is doing a SMC reset, that might do it. If you have never done one it's pretty simple. Here is the advice letter and instructions:

http://support.apple.com/kb/HT3964

_iMac SMC RESET_

• Shut down the computer.
• Unplug the computer's power cord.
• Press and hold the power button for 5 seconds.
• Release the power button.
• Attach the computers power cable.
• Press the power button to turn on the computer.

Let's see if that does it.

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Answer 5

teethdr Author

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Sep 2, 2010 8:03 PM in response to rkaufmann87

Ok, I've done a little more research. I was able to mount to much smaller external hard drives on my iMac no problem. The 2 that won't work are 320GB and 500GB and have external power supplies. I'm beginning to wonder if my USB ports aren't getting enough power. If so it has happened on both 27 inch iMacs that Apple has sent me this month.

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Answer 6

rkaufmann87

Level 10

143,850 points

Sep 2, 2010 8:18 PM in response to teethdr

That could be, so the drives you have are powered by the USB Bus? A possible solution is connecting them to a quality powered USB hub and then connecting that to the iMac. If the hub is suppling enough power to them then they should work.

Also distance matters, the longer the cable the lower the power. So if you use short USB cables (18" or so) with a powered hub that would improve your chances.

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