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Yesterday I bought an external drive and after reformatting it to ext4, Ubuntu could no longer "see" it. I asked for help, and eventually came to the conclusion that the drive was somewhat defective. So I returned it, and got a new one. Before reformatting it, I plugged it and discovered that Ubuntu (12.04) couldn't see it. I thought maybe I'd goofed up something in the OS, so I used my 32GB thumbdrive to back up my docs & needed files, and then installed Ubuntu (13.04) from scratch.

When I plugged in my external drive, the new OS still can't see it there. I ran some checks, and saw the output of dmesg actually does show it was detected, but otherwise there was NO sign of it in any other way.

How do I fix this? Is there a way to mount it even if I can't "see" it there?

Here's the output messages from a few things I checked this evening after I installed 13.04 & plugged in my external drive....

$ sudo fdisk -l

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x000539fb

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048   969058303   484528128   83  Linux
/dev/sda2       969060350   976771071     3855361    5  Extended
Partition 2 does not start on physical sector boundary.
/dev/sda5       969060352   976771071     3855360   82  Linux swap / Solaris


$ lsusb

Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 002: ID 8087:0020 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 001 Device 003: ID 04f2:b209 Chicony Electronics Co., Ltd 

---- after plugging in my 32GB thumbdrive ----

$ dmesg | tail -n 17

[  979.174904] usb 2-1.1: new high-speed USB device number 7 using ehci-pci
[  979.267866] usb 2-1.1: New USB device found, idVendor=0781, idProduct=5530
[  979.267874] usb 2-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  979.267879] usb 2-1.1: Product: Cruzer Glide
[  979.267884] usb 2-1.1: Manufacturer: SanDisk
[  979.267889] usb 2-1.1: SerialNumber: 200549636207BE00F894
[  979.268934] scsi6 : usb-storage 2-1.1:1.0
[  980.267711] scsi 6:0:0:0: Direct-Access     SanDisk  Cruzer Glide     1.26 PQ: 0 ANSI: 5
[  980.268959] sd 6:0:0:0: Attached scsi generic sg2 type 0
[  980.270467] sd 6:0:0:0: [sdb] 62530624 512-byte logical blocks: (32.0 GB/29.8 GiB)
[  980.274744] sd 6:0:0:0: [sdb] Write Protect is off
[  980.274753] sd 6:0:0:0: [sdb] Mode Sense: 43 00 00 00
[  980.275724] sd 6:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[  980.285663]  sdb: sdb1
[  980.289108] sd 6:0:0:0: [sdb] Attached SCSI removable disk
[  980.762302] systemd-hostnamed[3676]: Warning: nss-myhostname is not installed. Changing the local hostname might make it unresolveable. Please install nss-myhostname!
[ 1083.401263] sdb: detected capacity change from 32015679488 to 0
[ 1246.785895] usb 2-1.1: USB disconnect, device number 7

---- after plugging in my 2TB Toshiba Canvio external hard drive & then unplugged it ----

$ dmesg | tail -n 8

[ 1728.251102] usb 2-1.3: new high-speed USB device number 8 using ehci-pci
[ 1728.345301] usb 2-1.3: New USB device found, idVendor=0480, idProduct=d010
[ 1728.345309] usb 2-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 1728.345314] usb 2-1.3: Product: External USB 3.0
[ 1728.345319] usb 2-1.3: Manufacturer: Toshiba
[ 1728.345324] usb 2-1.3: SerialNumber: 20130114021358
[ 1728.346698] scsi7 : usb-storage 2-1.3:1.0
[ 1729.423255] usb 2-1.3: USB disconnect, device number 8

...as you can see, it's detected it, but I don't know how to access it or mount it. I can see that the 32GB thumbdrive was mounted automatically to sdb, but the external drive was simply detected and that's all. They were both plugged into the same USB port.

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Is the HDD formatted ans has a valid partition? –  thefourtheye Jun 2 '13 at 1:41
    
Yes. I hooked it up to Windows 8, and I can read & write files. It works via Windows 7 too. So I know the drive is fine. –  Zamphatta Jun 2 '13 at 1:43
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1 Answer 1

up vote 0 down vote accepted

You say it works in Windows 8, is that using the same hardware and port?

With the "disconnect" message ~1100ms after insertion, I wonder if the USB port doesn't have quite enough power for the drive.

See this article from Toshiba: http://forums.toshiba.com/t5/Drivers-and-Utilities-Knowledge/External-USB-3-0-Hard-Drive-not-recognized/ta-p/379941

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Oh wow, that answers a lot of mysteries. It looks like I need to get a different cable for this to work. Thanks! I was going bananas trying to figure out what I did wrong. –  Zamphatta Jun 2 '13 at 13:51
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