I can confirm this bug too, for me was the same things, with the latests kernels I have the similar output with dmesg: [ 1348.290418] scsi7 : SCSI emulation for USB Mass Storage devices [ 1348.290711] usb-storage: device found at 19 [ 1348.290716] usb-storage: waiting for device to settle before scanning [ 1353.289243] usb-storage: device scan complete [ 1353.291343] scsi 7:0:0:0: Direct-Access WDC WD10 EAVS-00D7B0 PQ: 0 ANSI: 2 CCS [ 1353.310715] sd 7:0:0:0: Attached scsi generic sg4 type 0 [ 1353.366547] sd 7:0:0:0: [sdd] 1953525168 512-byte logical blocks: (1.00 TB/931 GiB) [ 1353.375379] sd 7:0:0:0: [sdd] Write Protect is off [ 1353.375392] sd 7:0:0:0: [sdd] Mode Sense: 34 00 00 00 [ 1353.375400] sd 7:0:0:0: [sdd] Assuming drive cache: write through [ 1353.385208] sd 7:0:0:0: [sdd] Assuming drive cache: write through [ 1353.385227] sdd: sdd1 sdd2 [ 1353.438247] sd 7:0:0:0: [sdd] Assuming drive cache: write through [ 1353.438265] sd 7:0:0:0: [sdd] Attached SCSI disk [ 1353.808064] usb 1-4: reset high speed USB device using ehci_hcd and address 19 [ 1354.016068] usb 1-4: device descriptor read/64, error -71 [ 1354.328070] usb 1-4: device descriptor read/64, error -71 [ 1354.544093] usb 1-4: reset high speed USB device using ehci_hcd and address 19 [ 1354.752074] usb 1-4: device descriptor read/64, error -71 [ 1355.064081] usb 1-4: device descriptor read/64, error -71 [ 1355.280061] usb 1-4: reset high speed USB device using ehci_hcd and address 19 [ 1355.752052] usb 1-4: device not accepting address 19, error -71 [ 1355.864049] usb 1-4: reset high speed USB device using ehci_hcd and address 19 [ 1356.336046] usb 1-4: device not accepting address 19, error -71 [ 1356.336145] usb 1-4: USB disconnect, address 19 [ 1356.448053] usb 1-4: new high speed USB device using ehci_hcd and address 20 [ 1356.656087] usb 1-4: device descriptor read/64, error -71 [ 1356.968047] usb 1-4: device descriptor read/64, error -71 [ 1357.184052] usb 1-4: new high speed USB device using ehci_hcd and address 21 [ 1357.392045] usb 1-4: device descriptor read/64, error -71 [ 1357.704046] usb 1-4: device descriptor read/64, error -71 [ 1357.920067] usb 1-4: new high speed USB device using ehci_hcd and address 22 [ 1358.392044] usb 1-4: device not accepting address 22, error -71 [ 1358.504064] usb 1-4: new high speed USB device using ehci_hcd and address 23 [ 1358.976052] usb 1-4: device not accepting address 23, error -71 [ 1358.976100] hub 1-0:1.0: unable to enumerate USB device on port 4 [ 1359.432052] usb 2-4: new full speed USB device using ohci_hcd and address 16 [ 1359.612064] usb 2-4: device descriptor read/64, error -62 [ 1359.896046] usb 2-4: device descriptor read/64, error -62 [ 1360.176079] usb 2-4: new full speed USB device using ohci_hcd and address 17 [ 1360.356063] usb 2-4: device descriptor read/64, error -62 [ 1360.640052] usb 2-4: device descriptor read/64, error -62 [ 1360.920064] usb 2-4: new full speed USB device using ohci_hcd and address 18 [ 1361.328048] usb 2-4: device not accepting address 18, error -62 [ 1361.504063] usb 2-4: new full speed USB device using ohci_hcd and address 19 [ 1361.912047] usb 2-4: device not accepting address 19, error -62 [ 1361.912089] hub 2-0:1.0: unable to enumerate USB device on port 4 with others linux distributions works fine (so there's not a problem with the usb port, cable or motherboard). kubuntu karmic KDE 4.3 RC2 kernel 2.6.31-2-generic