External HD not recognised

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Hi all,
Does anyone know why my Toshiba EXT HD only works with my iMac when it is plugged in via a USB ext cable and not when it is plugged in directly?
 
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Can you describe what you mean by "plugged in directly?"
 
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Hi,
Plugged in directly meaning the USB lead that came with the external drive was plugged into a spare USB port on the back of my iMac and nothing works or is seen by the iMac,
so if I then unplug it from the mac and then i plug it into a USB extension cable it will work fine
 

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If one cable works and one doesn't - the one that doesn't work would be a bad cable.
 
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Thanks bobtomay but it is the same cable thad i am using to plug into the USB extension so if lead is bad it shouldn't work that way either?
It is strange that it will only work when plugged into the extension cable and not straight to the mac
 

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"Extension cable"? Is this a powered hub or attached to a powered hub?
 
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It is non powered, about 3 feet long with a USB plug on one end and a socket on the other
 

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I assume by now powered you mean it is not plugged into a powered hub? Could it be a cable similar to this one? If so, the cable may be providing additional power. There are a number of bus powered hard drives that do not play nicely with some Mac models due to power issues.
 
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USB 2.0 Extension Cable

The External HDD is a Toshiba 500GB and it comes with a short USB lead attached to it.
When I plug this into a USB socket on my iMac nothing happens and it is nor recognised in any way.

If i then unplug the Toshiba HHD from the iMac and then plug it into a simple USB extension lead similar to this one
USB 2.0 Extension Cable

It works! the iMac recognises it and I am able to use it, format it and have time machine back up to it.
I can't understand that why a simple USB extension lead that only serves the purpose of basically moving a USB port to the end of a cable so that you don't have to look around the back of the computer to find it makes the drive work? The External HDD should work by plugging it straight to the USB port of the iMac with out the need to use an extension.
 

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The External HDD is a Toshiba 500GB and it comes with a short USB lead attached to it.

By "attached to it" I'm assuming it can't be removed?

I've never seen a Toshiba external hard drive that had a USB 2 lead permanently attached to it. Can you give us the model number?
 
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By "attached to it" I'm assuming it can't be removed?

I've never seen a Toshiba external hard drive that had a USB 2 lead permanently attached to it. Can you give us the model number?

HI, Yes the drive has a USB cable that can be detached, although I never have.
The model number is: HDTB105EK3AA
 

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I just looked up your model Toshiba external hard drive. It's a USB 3.0 hard drive and therefore needs to use the special USB 3 cable. USB 3 cables can be plugged into a USB 2 connector on your Mac, however, the end that attaches to the drive has to be the special USB 3 connector.

You keep referring to the drive as USB 2. If the model number you gave me above is correct the drive is definitely a USB 3 type. So I'm thoroughly confused as to what exactly you've been doing with a USB 2 extension cable?

Here's the advertisement of the drive from Amazon.com:

Toshiba HDTB105EK3AA 500GB Stor.E Basics USB 3.0 2.5 Inch External Hard Drive - Black
 
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OK just to clarify,

The drive will only work when plugged into a USB extension cable, it will not work when i connect it without the USB extension cable.
The drive comes with a USB 3 connecting cable that plugs into the drive and then into the Mac, but using this method does not work.
To get the drive to work I use the same USB connecting cable that came with the drive and instead of plugging it directly into the mac, I have to use a USB extension cable and plug the drive into that and then plug the other end into the Mac. It will now work as normal.
So the USB 2 extension cable I only use to get the thing working, it should work without it but it doesn't
 
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Hi all,
Just been down to my local computer store and tried my drive on a iMac display model and the same thing happens on that too, the guy at the store had a spare drive cable that i tried and that didn't work either so concluded it was a faulty Toshiba drive. He said it was weird and he had never seen this problem before.

My iMac is the 27inch model running Mavericks and it is about 3 weeks old.
 
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OK just to clarify,

The drive will only work when plugged into a USB extension cable, it will not work when i connect it without the USB extension cable.
The drive comes with a USB 3 connecting cable that plugs into the drive and then into the Mac, but using this method does not work.
To get the drive to work I use the same USB connecting cable that came with the drive and instead of plugging it directly into the mac, I have to use a USB extension cable and plug the drive into that and then plug the other end into the Mac. It will now work as normal.
So the USB 2 extension cable I only use to get the thing working, it should work without it but it doesn't

Yes, please provide the iMac model/year and have you tried other USB slots on the back of the computer?

But, I'm still confused as to how you are getting this to work, so I'll post some pictures; first, the connection to your Toshiba HD (red arrow indicates the type of connection for USB 3, i.e. w/ the indentation); a second pic showing the cable that I assume came w/ your HD - connector w/ red arrow goes into your HD & the connector w/ the blue arrow goes into the USB 2 extension cable shown in the third image (the one you provided a link); then on the last pic, the connector w/ the red arrow goes into your iMac - is that correct? Dave

.

ToshibaUSB3.jpg

ToshibaCable.jpg

BelkinUSB2.png
 

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Hi all,
Just been down to my local computer store and tried my drive on a iMac display model and the same thing happens on that too, the guy at the store had a spare drive cable that i tried and that didn't work either so concluded it was a faulty Toshiba drive. He said it was weird and he had never seen this problem before.

My iMac is the 27inch model running Mavericks and it is about 3 weeks old.

OK, things are a lot clearer now. A defective drive would certainly explain what's happening. When you stated that the USB 2 cable made it work is why I thought you didn't know the drive was in fact USB 3. Hopefully, you can return the drive for a new one and be able to use the faster speed of USB 3.

Your new iMac ports are USB 3 and backward compatible for USB 2, but of course using USB 3 devices is best.
 
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Hi RadDave,
You got it! thats how I get it to work. and it will only work when connected like your pictures indicate.
 
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Hi all,
Just been down to my local computer store and tried my drive on a iMac display model and the same thing happens on that too, the guy at the store had a spare drive cable that i tried and that didn't work either so concluded it was a faulty Toshiba drive. He said it was weird and he had never seen this problem before.

My iMac is the 27inch model running Mavericks and it is about 3 weeks old.

OOPS - seems like I was putting together my post w/ pics at the same time you were composing the above - glad that you sorted out the issue, just seems quite odd? Dave :)
 
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Not that this will help much, but I have a USB3 external drive with the "indented" connector and an included cable that converts it to "regular" USB. No trouble self-powering it here on a 2009 MBP, so I know these things can work when "plugged in directly."
 
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I also use a USB 3 drive (WD) for Time Machine with my MBP. I don't understand why the OP's USB 3 drive won't work directly when plugged into a USB 3 port, but will work when plugged into a USB 2 extension cable. Will the USB 2 cable still work at USB 3 speed?

Nope - with that connection, the speed will be limited to the USB 2 standard; the USB 3 cable has just over twice the number of wires (4 vs. 9) w/ the faster speed also dependent on the use of two data paths (more info HERE, if interested). Dave :)
 

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