Insert your USB pen drive. Let it get detected and mounted. Open Terminal. Type The Following commands dmesg |tail -> here the ‘|’ key is the pipe, ie, the key before the backspace key(the upper one, so press shift) You’ll get something like sathya@shaman:~$ dmesg |tail [ 9921.681164] sda: Write Protect is off [ 9921.681174] sda: Mode Sense: 23 00 00 00 [ 9921.681178] sda: assuming drive cache: write through