Comment 11 for bug 466575

When safely removing a device with the option from the context menu the following error is generated.

"Unable to stop device
Error detaching: helper exited with exit code 1: sense buffer empty
Error SYNCHRONIZE CACHE for /dev/sdc: Success sense buffer empty
Error STOP UNIT for /dev/sdc: No such file or directory"

A screenshot of the warning dialogue, taken from a downstream duplicate: http://launchpadlibrarian.net/36693130/USB_Flash_Memory_error.png
This image says:
"Unable to stop USB Flash Memory
Error detaching: helper exited with error code 1: synchronize
cache(10): Fixed format, current; Sense key: Key=9
 Additional sense: Logical unit not ready, cause not reportable
  Info fld=0x0 [0]
Error SYNCHRONIZE CACHE for /dev/sdd: Success
start stop unit: transport: Host_status=0x07 [DID_ERROR]
Driver_status=0x00 [DRIVER_OK, SUGGEST_OK]

Error STOP UNIT for /dev/sdd: No such file or directory"

This bug was reported originally by Martin Thoma at Launchpad in Ubuntu at <https://launchpad.net/bugs/466575>.