I am having the same problem with my Nano V3.0 but on Lubuntu 12.04 LTS
I have 2 nanos i purchased on Amazon that worked out of the box, but when I came back after a time I was dealing with this error. After an Arduino reinstall it seemed to fix it, but I don't understand why and now I am having the same problem
Tonight, I was receiving 2 different errors:
1) avrdude: stk500_recv(): programmer not responding
2) avrdude: stk500_getsync(): not in sync: resp 0x00
after Arduino reinstall removal/reinstall via Synaptic, the second board is fine and driving a servo, but the first is still showing the _recv error listed as the thread topic. I have tried uploading as Arduino Uno and Nano, but receiving the same error.
The L led is blinking, but the Loop-Back test would not print back my text. Since the L led is blinking, I'm assuming I don't need to reburn the bootloader, but that would be my next guess unless anyone else has a suggestion.
The instructions for reinstalling the FTDI driver in Linux is rather complicated, and I'm hoping there is an easier fix since one of the two Nanos is now functional.
It seems that this is a relatively new problem specifically for Nano that is not limited to Mac OS, at least according to my searches.