Hello,
I'm bumping this problem up, It seems that the problem occur to some new users, I have read that this could be a problem with the board itself and need to be return.
1 - I have selected the rigth board
2 - I have selected the rigth Serial / com
3 - I have re-install everything (Driver & IDE)
4 - Other board (YUN) was running perfectly last week on the same machine
5 - I can't reset the board (tried 2-5 sec hold and 32-37 sec hold)
6 - Interesting fact the LED 13 on the board is constantly ON (sometimes it fades during upload porcess)
7 - I have tried with OSX same problem
8 - I have tried changing the COM number to a different one.
Thank you for helping, i'm a new user and can't wait to get started.
Regards,
Error: Arduino: 1.6.7 (Windows 10), Board: "Arduino/Genuino Uno"
Sketch uses 1,030 bytes (3%) of program storage space. Maximum is 32,256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2,039 bytes for local variables. Maximum is 2,048 bytes.
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x59
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x59
avrdude: stk500_recv(): programmer is not responding
Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x59
avrdude: stk500_recv(): programmer is not responding
...
i have the same problem 
did you solve it ?
Same problem here, we got two Arduino Genuino UNO r3, both got the same problem?
Somebody fixed it?
Got the same problem today :
Arduino:1.6.7 (Windows 7), Kort"Arduino/Genuino Uno"
Skissen bruker 1 676 bytes (5%) av program lagrings minnet. Maks er 32 256 bytes
Globale variabler bruker 25 bytes (1%) av dynamisk minne, som etterlater 2 023 bytes til lokale variabler. Maks er 2 048 bytes.
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x05
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x05
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x05
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x05
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x05
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x05
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x05
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x05
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x05
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x05
Problemer ved opplasting til kortet. Se http://www.arduino.cc/en/Guide/Troubleshooting#upload for forslag.