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I have two 128GB Lexar USB flash drives. Now, when I try to connect them with my MacBook, they are not mounted automatically and they do not show up in Disk Utility too.

But my MacBook does detect the USB flash drives, because I see something happening in the /dev folder

...
brw-r-----  1 root  operator  0x100000c 19 aug 20:38 /dev/disk2s1
brw-r-----  1 root  operator  0x100000b 19 aug 20:38 /dev/disk2 
brw-r-----  1 root  operator  0x100000e 19 aug 20:39 /dev/disk3s1
brw-r-----  1 root  operator  0x100000d 19 aug 20:39 /dev/disk3

When I try the following it seems to hang, no output, just waiting for ever:

$> diskutil list

So my question is, is there a way I can mount this USB flash drives or maybe format it again. I find it hard te believe that both keys do not work anymore.

BTW, the USB flash drives also didn't mount on a Windows machine.

Giacomo1968
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Jeanluca Scaljeri
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1 Answers1

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USB Flash Drives store their firmware on the NAND chips them selves, in that sense it's data like any other data. Data on NAND chips is subject to "charge bleed" and do data "fades". The more the flash drive was used, the 'weaker' the NAND becomes.

It should not be a surprise that USB Flash Drives stop functioning if just given enough time.

If the issue is just that, "charge bleed" then rewriting the data, the firmware in this case should produce a USB Flash Drive that's usable again. But this process isn't very straight forward at all.

As a first step you'd need to determine the controller and NAND models. Then using that information you need to find the matching MPtool from a website like usbdev.ru.

Tools like "Flash Drive Information Extractor" can help determine the controller and NAND models and provide other diagnostic information. For example, the tool not detecting the device at all is probably due to failing controller. The tool detecting the controller but not the NAND probably means the controller can not communicate with the NAND (so that could be physical problem).

Flash Drive Information Extractor

TBH, I'd jus replace the USB flash drives.