Intel iMac won't recognize new 1.5TB external hard drive

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Hi,

I have an iMac 3.06GHz Intel Core 2 Duo running OS X 10.6.8. I've been using an ADATA CH94 500GB external hard drive for drag-and-drop backup of my applications and documents folders. It's worked fine. True plug-and-play functionality. But the drag-and-drop method takes about six hours over my USB. So I wanted to switch to using Time Machine for the backups, but Time Machine says that 500GB isn't big enough for it to have elbow room to work. (Hmm... Time Machine must have really big elbows, because I have plenty of room left for my old drag-and-drop method.)

So I upgraded to an ADATA NH03 1.5 TB USB 3.0 Portable External Hard Drive ANH03-1TU3-CBK. This drive runs off house current instead of the USB on my computer like the other one. The blue power light comes on, and I feel it running when I lay my hand on it. Fairly quiet. PROBLEM: when I plug it in, the iMac doesn't recognize it at all. No error messages or anything. Disk Utility is blind to it. Apple menu "About Mac" details also blind to it.

I called ADATA, and the Tech person told me the drive is NTFS, to reformat it with a PC to FAT32. Don't have access to a PC, so that doesn't help. But I suspect my 500GB drive was formatted the same, and it works fine. He then suggested that maybe Apple has a limitation on external HD sizes. Frankly, that sounded silly, since plenty of Mac users have larger external HDs than mine. And the comments section on Amazon (where I got this drive) included happy iMac users.

So... does anyone here have experience with this drive, or similar issues with another drive and know the solution? I really want it to work.

Thanks!
 
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That tech support person doesn't have a clue. Disk Utility would have had no problem formatting the drive to FAT32, but that's not what you should be using anyway for a Time Capsule.

However, the bigger issue at hand is that Disk Utility can't even see the drive. Even with NTFS, you should be able to see the drive in Finder, and any drive should be visible in Disk Utility, no matter how it is formatted. Given that, my best guesses here are that the USB cable is faulty, or the USB port it is plugged into is faulty. Less likely is that there is a problem with the drive itself, or its enclosure.

I would try, in this order:
  1. Plug the drive into a different USB port. If that fails...
  2. Try a different USB cable. If it fails with a new cable...
  3. Test it on another computer to see if it is recognized, preferably with a cable known to be working.
With regards to the very slow speeds you were experiencing before, is the drive USB 2.0 compliant? What about the USB cable itself?
 
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I would try, in this order:
  1. Plug the drive into a different USB port. If that fails...
  2. Try a different USB cable. If it fails with a new cable...
  3. Test it on another computer to see if it is recognized, preferably with a cable known to be working.
With regards to the very slow speeds you were experiencing before, is the drive USB 2.0 compliant? What about the USB cable itself?


1. Plug the drive into a different USB port...... Tried all four on the back of my iMac, no difference. The older 500GB drive works fine in them all.

2. Try a different USB cable..... The USB cable that came with it has a special end that plugs into the drive. Looks kinda like a stacked 1+1/2 USB plug. I don't have access to anything similar.

3. Test it on another computer to see if it is recognized..... Using supplied cable, tested it on my old iMac (the one that looks like a lamp). It didn't recognize it either.

My older CH94 500GB drive is supposed to be 2.0, and comes with an attached USB cable. I actually have had two of these (gave one to a friend), and the speeds on them were the same.

Seems like the suspect list is narrowing down to the cable?
 
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If Disk Utility can't see the drive on either Mac, then it's almost certainly the cable or the drive. Until you can get a new cable, there's nothing else to do, short of perhaps trying it on a 3rd computer for kicks.

BTW… how was that CH94 formatted? It's supposed to be USB 2.0 compliant, as is your iMac, so those write speeds shouldn't be that slow.

EDIT: I just noticed that you think the old drive was formatted the same as the new. Since you were writing to the drive, and since OS X doesn't normally write to NTFS volumes without 3rd-party help, you likely are using a 3rd party driver to enable write access. The free NTFS-3G is notoriously slow, and if that's what you are using, that would easily explain why you had such slow write speeds.
 
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At the ADATA phone tech's recommendation, a few days ago I briefly installed NTFS-3G in an initial attempt to get my iMac to recognize the NH03 1.5tb drive, but when it didn't help I promptly uninstalled it. So that program was never used for any backups.

I just checked my CH94 with Disk Utility, and it's formatted FAT32. Is there a different formatting I could try via Disk Utility for increased efficiency? I'm only using Macs, no PCs, so cross-platforming isn't a top priority.
 
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ADATA tech support just confirmed NH03 external drive is formatted NTFS. The CH94 drive is formatted FAT32. My earlier assumption that both were formatted the same is incorrect. I have no idea why ADATA doesn't format them all the same for cross-platform compatibility, since the customer comments I read included Mac users for both models.
 

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First so I will not forget, you should format your drive Apple format (Mac OSX Extended Journalized). Since you are not using anything but Macs with OSX, that will be the way to go. Also Time Machine only works with Apples format.

I am wondering since it's a USB 3.0 drive and the ports on your Mac are USB 2.0 if the adapter cable is defective? Any working drive should show up in Disk Utility even if it will not mount.

Let us know if that cable does the trick.
 
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The replacement cable arrived today. Plugged it in, and within a few seconds the iMac recognized the external HD. Got it reformatted for Time Machine, and everything seems to work great! I am so relieved it turned out to be a cable and not the drive.

I haven't installed Lion yet (waiting for the USB stick to be available), so I decided to make this backup part of my upgrade preparations. Usually I pick and choose main folders, but this time I had it copy everything. That made this backup way bigger than usual. It took 4hr. 35min. to back up 578.77GB using the new USB cable. Considering the large size, that seems faster than what I'm use to, so I'm happy.

Thanks so much for your advice. It saved me a load of hassle, and I appreciate it. You guys are great!
 
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The replacement cable arrived today. Plugged it in, and within a few seconds the iMac recognized the external HD. Got it reformatted for Time Machine, and everything seems to work great! I am so relieved it turned out to be a cable and not the drive.

I haven't installed Lion yet (waiting for the USB stick to be available), so I decided to make this backup part of my upgrade preparations. Usually I pick and choose main folders, but this time I had it copy everything. That made this backup way bigger than usual. It took 4hr. 35min. to back up 578.77GB using the new USB cable. Considering the large size, that seems faster than what I'm use to, so I'm happy.

Thanks so much for your advice. It saved me a load of hassle, and I appreciate it. You guys are great!

Glad it worked out for you.

Before you invest $70 in a USB stick from the Apple Store, did you know Apple released a utility yesterday that you can put on a disc or flash drive/USB stick of your own and it acts as a recovery assistant similar to putting your SL disc in and restarting while holding "C"?Lion Recovery Disk Assistant

You install Lion from the Mac App Store ($30 USD) first, then follow that link I provided to download the recovery assistant to whatever drive/disc/USB stick you want. You save yourself about $40 USD. Just thought you might want to know.
 
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intel iMac won't recognize Toshiba portable (v63700c)

I got a 1TB Toshiba portable (v63700c) and it won't show up on my intel iMac (OS 10.6.8). It does, however, show up on my Power Mac G5 and I was able to reformat it with Disk Utility to Mac OS Extended (Journaled) and save some files on it.

After I did all that, I re-hooked it up to the iMac and it won't show up, nor does Disk Utility see it. I switched USB ports, too, and restarted then actually shut down several times.

I miss the old Norton Utilities where you could search out and mount all disks. I know Disk Utility is supposed to do that, but there's no option to "Search" for all available disks. If it doesn't show up, that's it for you.

I'd appreciate any suggestions on what else to do!
 

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