Prevent having to reset when uploading

Every time I upload my sketch into the Arduino, I have to reset the board in order to make it upload, otherwise I get an error ("stk500_recv(): programmer is not responding"). The problem wasn't there in the beginning, at some point I had to reset in order to get it working, I've tried it with 8 different arduino's and they all have this problem. So there has to be some problem with the Arduino software.

Is there a way to prevent this problem I want to embed a board into a project and I don't want to take it all apart each time to be able to reach the reset button.

I'm using MacOS 10.9.1 and Arduino 1.0.5. I upload using USB, without any hubs.

..must be a driver problem. DTR isnt triggered as it should be.

Yes there has to be something wrong with the software not sending a reset signal, or at the wrong time. Is there a way to modify this?

I found this in the docs

Drivers provide a way for software on your computer (i.e. the Arduino software) to talk to hardware you connect to your computer (the Arduino board). In the case of Arduino, the drivers work by providing a virtual serial port (or virtual COM port). The Arduino Uno and Mega 2560 use standard drivers (USB CDC) provided by the operating system to communicate with the ATmega8U2 on the board. Other Arduino boards use FTDI drivers to communicate with the FTDI chip on the board (or in the USB-serial convertor).

I have an Arduino Mega 2560 and I tried to upload, and it does work without resetting. So I guess there's something wrong with the FTDI drivers.

Ok i found the solution 8), I searched for the FTDI drivers and I downloaded the version for my OS here: VCP Drivers - FTDI

After installing, it worked perfectly. Hope this helps people with the same problem.