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3TB external USB3.0 won't mount

scienide09

scienide09

macrumors 65816
Original poster
May 5, 2007
1,385
0
Canada
Help!

I have an 3TB (Seagate) installed in an external enclosure (SATA) connected to my 2009 iMac via USB 3.0. The enclosure has a separate power supply which is plugged in.

No matter what I've tried, the drive won't mount, doesn't appear in Disk Utility, and doesn't appear as a USB-connected device in System Profilier

The drive, enclosure, and USB port all work -- I know this because I can connect, read/write, and see the drive in Windows 7 via virtualization.

I'm running MacFUSE and NTFS-3g, so it's not an issue with connecting an NTFS drive. To be certain, I reformatted (in windows) as both FAT32 and ExFAT. Neither worked to make the drive appear in OS X. Using a Windows tool (trial), I've even formatted as HFS+, but the drive still doesn't show on OS X.

Other things I've tried:
  • updading from 10.7.4 to 10.7.5
  • resetting SMC
  • powering on the computer, the drive, and plugging in the connection in different order combinations
  • connecting to different USB ports
  • using Recovery System to access Disk Utility at a higher lever

So far, nothing works, but the device continues to connect to Win7 just fine.

Any thoughts
 
wlossw said:
have you tried partitioning it as 2 smaller drives on another machine?
Click to expand...

So I tried this at your suggestion. I made 3 partitions so that none of them is larger than 1TB. Still no luck.

So I noticed while trying the above that my iMac is, somewhere, recognizing that something is attached to the USB port. In the attached image "after" you can see some device 6789012..... from ASMedia Technology Inc. This must be my drive, as this item is only present when the drive is attached and powered on.

Still nothing in Disk Utility, however.
 

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Last edited:
Find a USB 2.0 cable and try connecting.

The MBP is finicky, sensitive to cables and PCB layout for proper USB 3.0 connection. Make sure you have a good quality USB 3.0 cable. Some USB 3.0 connectors can also be finicky, preventing a proper connection.

Most likely it will connect properly as a USB 2.0 device on your MBP if you use a USB 2.0 cable.

Found this suggestion in the Apple Support forums.

Also, make sure your MBP is up-to-date will all updates. There was an update to the MBP to improve USB support a few weeks ago.

>>> Oops! Sorry for confusing MBP with your iMac. reading comprehension on vacation yesterday. In any case, do try a different cable.
>>> Also, there may be a firmware issue with your ASMedia chip inside the enclosure. OS X USB driver may be less tolerant than Windows USB driver.
 
Last edited:
>>> Oops! Sorry for confusing MBP with your iMac. My reading comprehension must have been on vacation yesterday. In any case, do try a different cable.

>>> Also, there may be a firmware issue with your ASMedia chip inside the enclosure. OS X USB driver may be less tolerant than Windows USB driver.
 
It is most likely the external sata enclosure.
We have a bunch of different enclosures that don't take anything over 2TB.

Most of them need firmware updates depending on their chip-set controller.
 
I'll second the recommendation to try, at least, a different cable. I have an external USB 3.0 enclosure that works spottily on my late 2008 aluminum unibody Macbook with a USB 3.0 cable but perfectly fine with a USB 2.0 cable. (Of course, it could just be a bad 3.0 cable that I have--it's a probably-cheap one that came with the drive, but I don't have a lot around to test with.) My AirPort Extreme is the same. My PC doesn't care.

It could be the enclosure, but it seems you've already verified that this size is supposed to be supported.

I'd be interested to hear if there are any updates.
 
Just a quick update to this.

I replaced the enclosure with a new one from a different vendor. It worked, first time. The staff I talked to at the store told me the first one is on the cheap-end of the scale -- weird, because the enclosure I originally purchased was recommended by their staff at a different store.

Anyway, happy now!
 
scienide09 said:
Just a quick update to this.

I replaced the enclosure with a new one from a different vendor. It worked, first time. The staff I talked to at the store told me the first one is on the cheap-end of the scale -- weird, because the enclosure I originally purchased was recommended by their staff at a different store.

Anyway, happy now!
Click to expand...

Thanks for the followup. Always nice to find out if the problem got resolved.
 
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