windows is unable to stop the device usb mass
April 13, 2016 9:05:11 PM. whenever I try to eject my hard drive I keep getting this error , and no the hdd isn't being used at all when I try to eject it . windows is unable to stop the device ' USB attached scsi ( UAS) mass storage device , don't remove this device while it is still in use close any programs using this device then remove it.