MacBook Pro (Early 2011) Not Recognizing Toshiba Canvio USB 3.0 Hard Drive

dustinrwh wrote:

I have heard that this may be possible without a USB power supply using just a USB 2.0 Y Cable

No. There's no magic inherent in a Y-cable, it's just adding an extra connector. Either the bus supplies enough power, or it doesn't. I suppose it is conceivable that a truly badly made cable might have enough internal resistivity to eat up sufficient current to bring the power on the bus below the minimum threshold, but that would have nothing to do with its being a straight cable or a Y-cable.

Hi

I have just bought the exact same harddrive and experiencing problems with my mid 2011 imac.

My other external drives (one usb powered, one with power supply) work without problem but this one does not light up, so it seems like a power issue. but strange thing is it lights up when i plug it into keyboards usb, but makes strange noises. And i plug it into my 15" MBP and it works without any problem.

so where is the problem? on my imacs USB port or toshiba external drive.

The drive may use more than USB 2.0 standard for power. Apple apparently limits every USB port to 500ma (USB 2.0 standard) and no more. Possible the extra data connections for USB 3.0 may actually draw some power. Or Apple somehow as some confusing signals going down the USB port. Either way, there's four ways to make it work:

1. Use a micro USB 2.0 connector as described above - that eliminates the USB 3.0 connectors on the hard drive. This seems to work for most people and did for me.

2. Connect the drive through a USB hub to the Mac or iMac. This worked for some people in this forum.

3. Connect the drive through a powered (has it's own power supply) USB hub to the Mac or iMac.

4. Connect using a Y cord - although I haven't heard many people reporting this working. This is an older technique from trying to power accessories from USB 1.0 ports.

Using USB 2.0 connectors instead of 3.0 doesn't degrade the drive speed on Macs - they don't support 3.0 rates anyway so you're limited to 2.0 performance no matter what.

Sorry if this is a dumb question. I'm having this same problem with new Macbook air. If I buy a micro USB where does the micro end plug into?

Both the MBA and the drive have the large USB port. I'm cofused where the small end would plug into.

Any assitance is appreciated as I already have a lot of time machine data on this drive that I'd like to keep.

If you look carefully at the picture of the HDD shown by dustinrwh, it looks like the micro end slips in on the right hand side. Look at it carefully and slide it it firmly, but do not try to force it in, just in case I am wrong. Note that with this drive you may need to have additional outboard power to supplement or replace that provided by the MBA.

Ciao.

I have that same external and mines worked for a few weeks and I formatted for mac. Now all of a sudden it stopped working. The only thing I can think of is that I recently took one of my memory sticks out becuase it was damamged. so I onl have 4 gigs in but I didn't think that would effect any HD