Macbook Air usb3 not working!

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Went to a client's today and tried to grab a 48GB database file from an external Toshiba USB 3 drive.

My brand-new macbook air couldn't read it. I don't want to point fingers at Apple,but when a harddrive works on any other machine but the MBAir, it's NOT the drive's problem it's my problem because I have an Apple

It's really embarassing to have this happen directly in front of a client with a brand new machine. Of course they all use PC's and I can see why...

I have a mid-2012 Air (120gb SSD/8gb RAM) and have had mixed experiences with USB 3 external HDDs.

I am using a WD 750GB external HDD partitioned for Time Machine and "mobile" backups of files, software etc = all good, no problems on USB 3 port on Air.

I also have a WD 3TB Caviar Green HDD in a mains-powered enclosure - sweet drive, quiet etc but the USB 3 port on the Air doesn't have the power to drive the WD drive (even with main supply). To access/use the 3TB drive, I have to connect it through a mains-powered USB hub.

Without the hub, I can hear the drive spinning up/spinning down and am unable to copy files to/from Air. Connected through powered USB hub, all is good.

any thoughts? anyone else with similar experiences?

I have a similar issue in that the external drives mount but them unmount themselves when in use and it driving me mad I think the issue is with the driver provided in OSx 10.7 since the drives work fine on an older MBA or Mbps so Apple need to fix this driver issue

I have done some more trialling and it is clear the USB 3 port on the mid-2012 MBA can not support external HDs except through a powered USB hub. I have tried a number of enclosures with other macs and the story is consistent. Clearly there is a problem with the USB 3 port on the MBA.

This is not universally true. I have a brand new MBA and it mounts and backs up fine to an external USB hard drive (a WD Passport Essential). It may be true that the MBA has problems with some external drives, perhaps having to do with current limitations. I had a similar issue with my 2010 MBA; I had to use a powered USB hub if I wanted to use BOTH an external drive and the ethernet adapter (unpowered wouldn't work).

Also, there are lots of reports about problems with the Toshiba drives long before the new MBA was announced.

Had same issue with MBA 11' 128GB. Have reported to Apple Care. Gone all the way up to engineers. No resolution yet. My issue was with a Verbatim 64GB USB 3.0 flash drive. Verbatim pointing at Apple. And yes, this same flash drive worked in 2010 MBP. Waiting and waiting... gotta be a firmware upgrade coming at some point.

Regarding the problems with USB 3 and external storage: Is there something weird going on with USB 3 on-board interfaces?

I was able to fiddle with an ASUS 1225B 11.6" notebook with the AMD CPU. I could not get the front left-side USB 3 port to recognize any of 6 different Kensington or HP USB thumb drives of different models and capacity. The rear USB 3 port was fine. The front port had no problem with a Logitech wired USB mouse.

Has anybody had problems with any of the USB 3 ports recognizing an external thumb drive?

I have a USB 3 thumb drive - Kingston Digital Data Traveler Ultimate 3.0 Generation 2 - which works just fine on my MacBook Air mid-2012 13" 8GB machine. The USB ports on the MacBook Air support both USB 2 and USB 3, but I can tell from the transfer speed to the thumb drive that it's working as a USB 3.

I have the exact same issue!

I have a 2012 MBA and a Toshiba Canvio USB 3.0 external drive that's partitioned for Time Machine and misc. files.

- The drive gets mounted most of the time. But sometimes it either does not mount, or the icons show up but the drives are inaccessible.

- The dive often disappears on the Mac, then Mac complians to me for not ejecting it properly.

I would love to see a solution soon!

Same issue here. My external drive keeps randomly disconnecting.

Actually it seems that the problem is related to external driver power consumption. The MBA just doesn't deliver enough current to power the drive. However the ports on 2012 MBA are able to provide some extra power (as verified by connecting the iPad to the USB port). When I connect the external drive to my MBA I'm getting the following values in System Information:

Current Available (mA): 900

Current Required (mA): 224

Obviously that's not enough to power the external drive (WD passport 1 TB USB 3.0). However when connecting the iPad I'm getting:

Current Available (mA): 500

Current Required (mA): 500

Extra Operating Current (mA): 1600

That's exactly 2.1 A of current - sufficient to power any external device. If I only knew how to force the port to supply more current to the external drive, my problem would be solved. Anyone has any idea how to fiddle with the power values on the USB bus ?

All the updates installed - running the latest version of Mountain Lion. I was hoping that "...and it improves compatibility with some USB devices." was related to my external drive issues, but apparently not.

I used to have the same problem: the WD Passport would mount on all other computers, except on the new MBA. As discussed already, it's probably caused by a lower power throughput. I then tried replacing the original USB3 cable with another (longer) one which I use for a large external HDD drive. It did the trick - it now works without problems.

My assumption is that the connection to the drive might not be that "tight" (I've had connection issues with my MBP and USB 2 WD Passport drives in the past as well). As soon as the power goes beneath a certain threshold, the bad connection isn't able to overcome its resistance. The better connection of another cable/plug decreases that resistance, therefore solving the problem.

Give it a try.

Thanks for your advice. I tried it with my USB 3.0 hub cable - the MBA wouldn't detect the drive at all. Will try tomorrow with a premium Lindy USB cable, maybe that will work. Strangely enough the WD Passport works through the USB 3.0 hub without issues using the WD provided cable.