USB-memory not recognized by imac

[iau]

I have a 32 GB USB flash memory that only shows up in Finder on my MacBook, but not iMac. Both running Lion with the latest updates. I have reformatted the thing several times, including once on a Windows computer. I chose the GUID Partition Table and Mac OS Extended (Journaled).

I compare it to a different USB memory and they seem identical, except that on the 32 GB shows a blueish color at the top and the rest is white, while the other is all blue. I only have one partition on both flash memory.

I treid asking the same question over at the Apple Support forum, but no response there. Hope I have better luck here.

Thanks in advance!
- iau

 

[simsaladimbamba]

How does it show up in Disk Utility? Is it mounted?
Can you make a screenshot of the Disk Utility window and attach it to your next post?

 

[iau]

Thanks for your reply! Here is a screenshot of the Disk Utility how it shows up on my MacBook (where it also mounts in Finder).

While it doesn't mount on my iMac I think it recognizes it in the System Report-window.

 

[simsaladimbamba]

Looks good. I guess it doesn't even show up in Disk Utility on the iMac?

 

[imthenachoman]

I have noticed the same problem with certain brands of sticks like the PNY. Which do you have?

 

[iau]

No, it doesn't show up in Disk Utility on the iMac either. Also tried it on a friends iMac but it didn't recognize it.

It's a Super Talent Flash 32GB Pico-C, Gold.

 

[Mr. Retrofire]

@iau & others:
I had also connection (or USB-protocol?) problems with certain flash drives on my Mid-2009 MBP (Mac OS X 10.6.8). The same flash drives work without a problem, and without reformatting on my Early-2011 Sandy Bridge i7 Quad-Core MBP. The flash drives which have problems are the CnMemory flash drives with the USBest controller. No problems with Transcend and Kingston flash drives (which use unknown other controllers).

----------

It's a Super Talent Flash 32GB Pico-C, Gold.

Look what i found via Google:

"The controller chip inside the Pico-C is USBest's UT-165 and uses chip-on-board technology."
from
http://aphnetworks.com/reviews/super_talent_pico_c_gold_8gb

That explains your connection (or USB protocol) problems. Good to hear that i'm not alone with this problem.

Solution:
Use Google before you buy an USB flash drive!

 

[iau]

Not sure I understand, but are you saying the problem is the CnMemory Flash? I'm pretty sure I have used it on my iMac before but it haven't been used that much. I only know for sure that I have used it on the MacBook.

And it works fine on my late-2008 MacBook, but not my mid-2010 iMac or a friends 2011 iMac.

 

[Mr. Retrofire]

Not sure I understand, but are you saying the problem is the CnMemory Flash?

The USB mass storage controller inside the flash drive has probably a faulty USB-protocol implementation. The other side (your PC or Mac) uses different USB-chipsets, depending on the hardware version, which can result in a different behavior. The behavior of your Mac or PC depends also on the USB drivers which your OS provides. Apple has implemented workarounds for certain USB devices, but probably not for the USBest controllers.

 

[iau]

When looking at the properties for the USB drive in System Reports, it says contents on this faulty UBS is Apple_hfs while my other USBs are EFI. Could that be a reason?

I did a search on Google and found something about files left after installation of Mac OS. I did use this USB to boot from once. Although it's only one partition it seems that 116 MB is taken by some mysterious files.