Linux tips

External USB hard drive not recognized

Symptoms

After plugging your USB hard drive in, nothing happens and the shell command

tail /var/log/messages

delivers something along these lines:

kernel: [63801.445541] usb 1-3: new high speed USB device using ehci_hcd and address 3
kernel: [63801.579191] usb 1-3: configuration #1 chosen from 1 choice
kernel: [63801.636280] scsi7 : SCSI emulation for USB Mass Storage devices
kernel: [63812.925573] usb 1-3: USB disconnect, address 3
kernel: [63812.927228] scsi 7:0:0:0: Device offlined - not ready after error recovery

What worked for me

1. disconnect the hard drive
2. set the jumper of the hard drive to “master”
3. reconnect the hard drive