[Evan K. Stone | Senior iOS Developer | Cloud City Development | http://www.cloudcity.io]

I just ran into this, being new to TinyCircuits/TinyDuino and thought I would post this just for anyone coming along that might have the same problem...

Basically, I attempted to follow the Getting Started steps (including installing the VCP drivers) and upload the Blink sketch and received a "programmer is not responding... not in sync... problem uploading to board" error:

Arduino: 1.6.3 (Mac OS X), Board: "Arduino Pro or Pro Mini, ATmega328 (3.3V, 8 MHz)"

Sketch uses 1,030 bytes (3%) of program storage space. Maximum is 30,720 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=0x00
...

However after a quick email exchange with support, they pointed out that there is a tiny ON/OFF switch on the main microcontroller board, and to toggle it back and forth. (I noticed that mine was actually set to "OFF" which probably didn't help matters.  )

But anyway, after flipping the switch a couple times and leaving it in the ON position, the upload worked just fine -- and I now have a functioning blinking TinyDuino! 

Thanks to the awesome support folks at TinyCircuits!

  yes, it's a very Tiny switch.

One of our designers made a 3D printed handle for the switch. Maybe we need to get some of those out for customers to use.