I have similar issue as below. but when I changed the 101 board, it works.
I can't use that board which had upload issue?
Arduino: 1.6.10 (Windows 10), Board: "Arduino/Genuino 101"
Sketch uses 17,244 bytes (11%) of program storage space. Maximum is 155,648 bytes.
Starting download script...
Flashing is taking longer than expected
Try pressing MASTER_RESET button
ERROR: Device is not responding.
ERROR: Device is not responding.
This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.