Hi, I can confirm I have the same issue on Ubuntu Ubuntu 12.04.3 LTS. I've posted a long comment on Bug #1176355 only to realise that it was a duplicate of this case. However, I see a lot of people are complaining about this being an issue on 13.04 or 13.10 whereas I have this issue on 12.04 but only since an update sometime around the start of December. Here is my comment from the other case - please excuse the length: Hi, I have the same issue but it seems to affect ALL USB disks. I unfortunately only have 1 on me right now but this disk does work on Windows and I'm fairly certain that I had no USB issues in November 2013, I suspect an update in December messed things up. I have also tried with 2 other USB disks which did work previously and they also are not working. DMESG Ouptput: [33712.381565] usb 1-1.2: new high-speed USB device number 4 using ehci_hcd [33712.553269] usb 1-1.2: New USB device found, idVendor=0011, idProduct=7788 [33712.553273] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [33712.553276] usb 1-1.2: Product: Mass Storage [33712.553278] usb 1-1.2: Manufacturer: Generic [33712.553280] usb 1-1.2: SerialNumber: 29F9C21B [33712.553948] scsi5 : usb-storage 1-1.2:1.0 [33713.552907] scsi 5:0:0:0: Direct-Access Generic Flash Disk 8.00 PQ: 0 ANSI: 2 [33713.553945] sd 5:0:0:0: Attached scsi generic sg2 type 0 [33713.555480] sd 5:0:0:0: [sdb] 16691200 512-byte logical blocks: (8.54 GB/7.95 GiB) [33713.556071] sd 5:0:0:0: [sdb] Write Protect is off [33713.556074] sd 5:0:0:0: [sdb] Mode Sense: 03 00 00 00 [33713.556572] sd 5:0:0:0: [sdb] No Caching mode page present [33713.556576] sd 5:0:0:0: [sdb] Assuming drive cache: write through [33713.559217] sd 5:0:0:0: [sdb] No Caching mode page present [33713.559222] sd 5:0:0:0: [sdb] Assuming drive cache: write through [33713.609029] sdb: sdb1 [33713.611489] sd 5:0:0:0: [sdb] No Caching mode page present [33713.611494] sd 5:0:0:0: [sdb] Assuming drive cache: write through [33713.611497] sd 5:0:0:0: [sdb] Attached SCSI removable disk [33744.352957] usb 1-1.2: reset high-speed USB device number 4 using ehci_hcd [33775.322639] usb 1-1.2: reset high-speed USB device number 4 using ehci_hcd [33806.228316] usb 1-1.2: reset high-speed USB device number 4 using ehci_hcd [33837.134160] usb 1-1.2: reset high-speed USB device number 4 using ehci_hcd [33868.167673] usb 1-1.2: reset high-speed USB device number 4 using ehci_hcd [33899.073388] usb 1-1.2: reset high-speed USB device number 4 using ehci_hcd [33899.241280] sd 5:0:0:0: [sdb] Media Changed [33899.241285] sd 5:0:0:0: [sdb] [33899.241287] Result: hostbyte=DID_ABORT driverbyte=DRIVER_SENSE [33899.241289] sd 5:0:0:0: [sdb] [33899.241290] Sense Key : Unit Attention [current] [33899.241294] Info fld=0x0 [33899.241296] sd 5:0:0:0: [sdb] [33899.241299] Add. Sense: Not ready to ready change, medium may have changed [33899.241301] sd 5:0:0:0: [sdb] CDB: [33899.241303] Read(10): 28 00 00 fe af f8 00 00 01 00 [33899.241311] end_request: I/O error, dev sdb, sector 16691192 [33899.241315] Buffer I/O error on device sdb, logical block 2086399 [33899.245484] sd 5:0:0:0: [sdb] No Caching mode page present [33899.245489] sd 5:0:0:0: [sdb] Assuming drive cache: write through [33899.247723] sd 5:0:0:0: [sdb] No Caching mode page present [33899.247728] sd 5:0:0:0: [sdb] Assuming drive cache: write through [33899.297542] sdb: sdb1 [33929.979207] usb 1-1.2: reset high-speed USB device number 4 using ehci_hcd lsusb -v: Bus 001 Device 004: ID 0011:7788 Couldn't open device, some information will be missing Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 0 (Defined at Interface level) bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x0011 idProduct 0x7788 bcdDevice 1.03 iManufacturer 1 iProduct 2 iSerial 3 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 32 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0x80 (Bus Powered) MaxPower 100mA 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 0x01 EP 1 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x82 EP 2 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 sudo fdisk -l: (this hangs for quite a while on sdb - I've posted the dmesg output below as well to show the hang) WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted. Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 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: 0x00000000 Device Boot Start End Blocks Id System /dev/sda1 1 1953525167 976762583+ ee GPT [34242.648865] INFO: task fdisk:30025 blocked for more than 120 seconds. [34242.648868] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [34242.648870] fdisk D ffffffff8180cb60 0 30025 30024 0x00000000 [34242.648876] ffff88003c28f8d8 0000000000000086 0000000000013980 0000000000000001 [34242.648880] ffff88003c28ffd8 ffff88003c28ffd8 ffff88003c28ffd8 0000000000013980 [34242.648884] ffffffff81c13460 ffff8800266e8000 ffff88011e2939f0 7fffffffffffffff [34242.648887] Call Trace: [34242.648896] [] schedule+0x29/0x70 [34242.648899] [] schedule_timeout+0x2a5/0x320 [34242.648905] [] ? ttwu_do_activate.constprop.84+0x66/0x70 [34242.648908] [] ? ttwu_queue+0xd6/0xf0 [34242.648912] [] wait_for_common+0xdf/0x180 [34242.648916] [] ? try_to_wake_up+0x200/0x200 [34242.648919] [] wait_for_completion+0x1d/0x20 [34242.648924] [] wait_on_work+0x191/0x1a0 [34242.648927] [] ? do_work_for_cpu+0x30/0x30 [34242.648932] [] __cancel_work_timer+0x73/0x80 [34242.648935] [] cancel_delayed_work_sync+0x12/0x20 [34242.648940] [] disk_block_events+0x98/0xa0 [34242.648944] [] __blkdev_get+0x73/0x480 [34242.648947] [] ? blkdev_get+0x1e0/0x1e0 [34242.648950] [] blkdev_get+0x5e/0x1e0 [34242.648952] [] ? blkdev_get+0x1e0/0x1e0 [34242.648955] [] blkdev_open+0x5d/0x80 [34242.648959] [] do_dentry_open+0x22e/0x2b0 [34242.648963] [] __dentry_open+0x18/0x70 [34242.648966] [] vfs_open+0x3d/0x40 [34242.648969] [] nameidata_to_filp+0x58/0xa0 [34242.648973] [] do_last+0x4bc/0x850 [34242.648977] [] path_openat+0xd6/0x440 [34242.648980] [] ? __queue_work+0xe0/0x330 [34242.648984] [] do_filp_open+0x42/0xa0 [34242.648988] [] ? _raw_spin_lock+0xe/0x20 [34242.648993] [] ? alloc_fd+0xd1/0x120 [34242.648996] [] do_sys_open+0xf4/0x230 [34242.649000] [] ? fput+0x25/0x30 [34242.649003] [] sys_open+0x21/0x30 [34242.649007] [] system_call_fastpath+0x16/0x1b [34271.220012] usb 1-1.2: reset high-speed USB device number 4 using ehci_hcd [34271.388040] sd 5:0:0:0: [sdb] Media Changed [34271.388044] sd 5:0:0:0: [sdb] [34271.388046] Result: hostbyte=DID_ABORT driverbyte=DRIVER_SENSE [34271.388048] sd 5:0:0:0: [sdb] [34271.388050] Sense Key : Unit Attention [current] [34271.388054] Info fld=0x0 [34271.388056] sd 5:0:0:0: [sdb] [34271.388058] Add. Sense: Not ready to ready change, medium may have changed [34271.388061] sd 5:0:0:0: [sdb] CDB: [34271.388062] Read(10): 28 00 00 fe af f8 00 00 01 00 [34271.388070] end_request: I/O error, dev sdb, sector 16691192 [34271.388074] Buffer I/O error on device sdb, logical block 2086399 [34271.391112] sd 5:0:0:0: [sdb] No Caching mode page present [34271.391117] sd 5:0:0:0: [sdb] Assuming drive cache: write through [34271.393358] sd 5:0:0:0: [sdb] No Caching mode page present [34271.393362] sd 5:0:0:0: [sdb] Assuming drive cache: write through [34271.443174] sdb: sdb1 [34302.125860] usb 1-1.2: reset high-speed USB device number 4 using ehci_hcd [34333.031689] usb 1-1.2: reset high-speed USB device number 4 using ehci_hcd This is a major issue for me as I can only access my Ubuntu machine via the network and this was working 1 month ago. Rowan