external USB hd

[Darksidex]

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When I attach my external USB2.0 HD I get the next message:

umass0: Cypress Semiconductor USB2.0 Storage Device, rev 2.00/0.01, addr 2
umass0: Get Max Lun not supported (STALLED)
da0 at umass-sim0 bus 0 target 0 lun 0
da0: <ST320082 2A \\0000\\0000> Fixed Direct Access SCSI-0 device
da0: 1.000MB/s transfers
da0: 190782MB (390721968 512 byte sectors: 255H 63S/T 24321C)

Why I get "umass0: Get Max Lun not supported (STALLED)"?
This means that my device or my hd isn't well supported?
Can I do something to fix it? Because sometimes my computer becomes halted.
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