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I'm having a problem with a USB thumb drive that I used to be able to read and write to with no issues. On two different Macs: MacBook Pro and iMac, it doesn't mount. It doesn't even show up in DiskUtility. The only thing that happens when it gets plugged in is that dmesg shows the line USBMSC Identifier (non-unique): 0x58f 0x1234 0x1. I checked System Profiler and it showed the following for the device:

Mass Storage Device:

  Product ID:   0x1234
  Vendor ID:    0x058f  (Alcor Micro, Corp.)
  Version:   0.01
  Speed:    Up to 480 Mb/sec
  Manufacturer: Alcor Micro
  Location ID:  0xfa200000 / 2
  Current Available (mA):   500
  Current Required (mA):    100

Which to me looks like everything's good. Through some googleing I found out about USB Prober. Someone said that after running USB Prober their drive showed up. I ran the tool, but my drive didn't appear, and it showed this output for my device:

High Speed device @ 2 (0xFA200000): .............................................   Composite device: "Mass Storage Device"
    Port Information:   0x001a
           Not Captive
           Attached to Root Hub
           External Device
           Connected
           Enabled
    Device Descriptor   
        Descriptor Version Number:   0x0200
        Device Class:   0   (Composite)
        Device Subclass:   0
        Device Protocol:   0
        Device MaxPacketSize:   64
        Device VendorID/ProductID:   0x058F/0x1234   (Alcor Micro, Inc.)
        Device Version Number:   0x0001
        Number of Configurations:   1
        Manufacturer String:   1 "Alcor Micro"
        Product String:   2 "Mass Storage Device"
        Serial Number String:   0 (none)
    Configuration Descriptor   
        Length (and contents):   32
            Raw Descriptor (hex)    0000: 09 02 20 00 01 01 00 80  32 09 04 00 00 02 08 06  
            Raw Descriptor (hex)    0010: 50 00 07 05 01 02 00 02  00 07 05 82 02 00 02 00  
            Unknown Descriptor   0020: 
        Number of Interfaces:   1
        Configuration Value:   1
        Attributes:   0x80 (bus-powered)
        MaxPower:   100 ma
        Interface #0 - Mass Storage/SCSI   
            Alternate Setting   0
            Number of Endpoints   2
            Interface Class:   8   (Mass Storage)
            Interface Subclass;   6   (SCSI)
            Interface Protocol:   80
            Endpoint 0x01 - Bulk Output   
                Address:   0x01  (OUT)
                Attributes:   0x02  (Bulk no synchronization data endpoint)
                Max Packet Size:   512
                Polling Interval:   0 ( Endpoint never NAKs)
            Endpoint 0x82 - Bulk Input   
                Address:   0x82  (IN)
                Attributes:   0x02  (Bulk no synchronization data endpoint)
                Max Packet Size:   512
                Polling Interval:   0 ( Endpoint never NAKs)
    Device Qualifier Descriptor   
        Descriptor Version Number:   0x0200
        Device Class   0   (Composite)
        Device Subclass   0
        Device Protocol   0
        Device MaxPacketSize:   64
        Number of Configurations:   1
        bReserved:   0
    Other Speed Configuration Descriptor   
        Length (and contents):   32
            Raw Descriptor (hex)    0000: 09 07 20 00 01 01 00 80  32 09 04 00 00 02 08 06  
            Raw Descriptor (hex)    0010: 50 00 07 05 01 02 40 00  00 07 05 82 02 40 00 00  
            Unknown Descriptor   0020: 
        Number of Interfaces:   1
        Configuration Value:   1
        Attributes:   0x80 (bus-powered)
        MaxPower:   100 ma
        Interface #0 - Mass Storage/SCSI   
            Alternate Setting   0
            Number of Endpoints   2
            Interface Class:   8   (Mass Storage)
            Interface Subclass;   6   (SCSI)
            Interface Protocol:   80
            Endpoint 0x01 - Bulk Output   
                Address:   0x01  (OUT)
                Attributes:   0x02  (Bulk no synchronization data endpoint)
                Max Packet Size:   64
                Polling Interval:   0 ms
            Endpoint 0x82 - Bulk Input   
                Address:   0x82  (IN)
                Attributes:   0x02  (Bulk no synchronization data endpoint)
                Max Packet Size:   64
                Polling Interval:   0 ms

Everything looks like it's all set for a USB drive, I don't understand why it's not mounting.

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did you find a solution? –  laktak Aug 26 '13 at 13:37

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