Ubuntu 12.10 64 bit seems not to recognize my external hard disk. It is a Vantec NST-310S3 external disk enclosure with a WD 3TB drive. The disk has two NTFS partitions. My PC is a dual boot system. Under Windows 7 the hard disk works fine but I can't make it work with Ubuntu. When the drive is connected to the PC then the command sudo fdisk -l seems to hang forever. Below are the output of lsusb and cat /proc/partitions without the external drive and then with it connected. I added also the last lines of the dmesg command at the end. First without the drive: ilan@linux:~$ lsusb Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 13ba:0017 Unknown PS/2 Keyboard+Mouse Adapter Bus 001 Device 004: ID 046d:c50e Logitech, Inc. Cordless Mouse Receiver Bus 001 Device 005: ID 0ac8:3420 Z-Star Microelectronics Corp. Venus USB2.0 Camera ilan@linux:~$ cat /proc/partitions major minor #blocks name 8 0 1953514584 sda 8 1 102400 sda1 8 2 629043200 sda2 8 3 367001600 sda3 8 4 1 sda4 8 5 471859200 sda5 8 6 157286400 sda6 8 7 324115456 sda7 8 8 4101120 sda8 11 0 1048575 sr0 Second with the USB 3 drive: ilan@linux:~$ lsusb Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 004 Device 002: ID 174c:55aa ASMedia Technology Inc. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 13ba:0017 Unknown PS/2 Keyboard+Mouse Adapter Bus 001 Device 004: ID 046d:c50e Logitech, Inc. Cordless Mouse Receiver Bus 001 Device 005: ID 0ac8:3420 Z-Star Microelectronics Corp. Venus USB2.0 Camera ilan@linux:~$ cat /proc/partitions major minor #blocks name 8 0 1953514584 sda 8 1 102400 sda1 8 2 629043200 sda2 8 3 367001600 sda3 8 4 1 sda4 8 5 471859200 sda5 8 6 157286400 sda6 8 7 324115456 sda7 8 8 4101120 sda8 11 0 1048575 sr0 8 16 2930266584 sdb ilan@linux:~$ lsusb -v -s 004:002 Bus 004 Device 002: ID 174c:55aa ASMedia Technology Inc. Couldn't open device, some information will be missing Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 3.00 bDeviceClass 0 (Defined at Interface level) bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 9 idVendor 0x174c ASMedia Technology Inc. idProduct 0x55aa bcdDevice 1.00 iManufacturer 2 iProduct 3 iSerial 1 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 44 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xc0 Self Powered MaxPower 0mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 2 bInterfaceClass 8 Mass Storage bInterfaceSubClass 6 SCSI bInterfaceProtocol 80 Bulk-Only iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0400 1x 1024 bytes bInterval 0 bMaxBurst 15 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x02 EP 2 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0400 1x 1024 bytes bInterval 0 bMaxBurst 15 ilan@linux:~$ sudo fdisk -l [sudo] password for ilan: Disk /dev/sda: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xf1b4f1ee Device Boot Start End Blocks Id System /dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sda2 206848 1258293247 629043200 7 HPFS/NTFS/exFAT /dev/sda3 1258293248 1992296447 367001600 7 HPFS/NTFS/exFAT /dev/sda4 1992298494 3907028991 957365249 f W95 Ext'd (LBA) /dev/sda5 1992298496 2936016895 471859200 7 HPFS/NTFS/exFAT /dev/sda6 2936018944 3250591743 157286400 7 HPFS/NTFS/exFAT /dev/sda7 3250593792 3898824703 324115456 83 Linux /dev/sda8 3898826752 3907028991 4101120 82 Linux swap / Solaris dmesg output after connecting the external drive: [ 23.740567] e1000e: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx [ 23.740786] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready [ 49.144673] usb 4-1: >new SuperSpeed USB device number 2 using xhci_hcd [ 49.163039] usb 4-1: >Parent hub missing LPM exit latency info. Power management will be impacted. [ 49.166789] usb 4-1: >New USB device found, idVendor=174c, idProduct=55aa [ 49.166793] usb 4-1: >New USB device strings: Mfr=2, Product=3, SerialNumber=1 [ 49.166796] usb 4-1: >Product: AS2105 [ 49.166799] usb 4-1: >Manufacturer: ASMedia [ 49.166801] usb 4-1: >SerialNumber: 0123456789ABCDEF [ 49.206372] usbcore: registered new interface driver uas [ 49.228891] Initializing USB Mass Storage driver... [ 49.229042] scsi6 : usb-storage 4-1:1.0 [ 49.229115] usbcore: registered new interface driver usb-storage [ 49.229116] USB Mass Storage support registered. [ 64.045528] scsi 6:0:0:0: >Direct-Access WDC WD30 EZRX-00MMMB0 80.0 PQ: 0 ANSI: 0 [ 64.046224] sd 6:0:0:0: >Attached scsi generic sg2 type 0 [ 64.046881] sd 6:0:0:0: >[sdb] Very big device. Trying to use READ CAPACITY(16). [ 64.047610] sd 6:0:0:0: >[sdb] 5860533168 512-byte logical blocks: (3.00 TB/2.72 TiB) [ 64.048368] sd 6:0:0:0: >[sdb] Write Protect is off [ 64.048373] sd 6:0:0:0: >[sdb] Mode Sense: 23 00 00 00 [ 64.048984] sd 6:0:0:0: >[sdb] No Caching mode page present [ 64.048987] sd 6:0:0:0: >[sdb] Assuming drive cache: write through [ 64.049297] sd 6:0:0:0: >[sdb] Very big device. Trying to use READ CAPACITY(16). [ 64.050942] sd 6:0:0:0: >[sdb] No Caching mode page present [ 64.050944] sd 6:0:0:0: >[sdb] Assuming drive cache: write through [ 94.245006] usb 4-1: >reset SuperSpeed USB device number 2 using xhci_hcd [ 94.262553] usb 4-1: >Parent hub missing LPM exit latency info. Power management will be impacted. [ 94.263805] xhci_hcd 0000:03:00.0: >xHCI xhci_drop_endpoint called with disabled ep ffff8800d37d1c00 [ 94.263808] xhci_hcd 0000:03:00.0: >xHCI xhci_drop_endpoint called with disabled ep ffff8800d37d1c40 [ 125.262722] usb 4-1: >reset SuperSpeed USB device number 2 using xhci_hcd [ 125.280304] usb 4-1: >Parent hub missing LPM exit latency info. Power management will be impacted. [ 125.281511] xhci_hcd 0000:03:00.0: >xHCI xhci_drop_endpoint called with disabled ep ffff8800d37d1c00 [ 125.281516] xhci_hcd 0000:03:00.0: >xHCI xhci_drop_endpoint called with disabled ep ffff8800d37d1c40