user2817: I've been using my Arduino UNO without a hith for a few days now, but suddenly I can't program it anymore.
When I try to programm my Arduino on Mac, I get the following Error:
avrdude: stk500_recv(): programmer is not responding

The USB option under serial port has disappeard (It was there before). Has anyone an idea on how to fix this?
The last thing I did is use the serial port for some communication. A reboot hasn't improved anything.
I tried programming Linux, but it resulted in the exact same result.

user313: If I try to upload with no device connected, I get a dialog with the message "port is blocked" and a message in Eclipse's console window that the port is not found.
So I'm guessing you've got a sync problem. UNO should reset automatically when avrdude connects. Try manually resetting it just before you click to start the download. If that works, then the automatic reset has failed.

user2817: It seemed to be a hardware problem on the board. Thanks for the effort.

2817: <p>I've been using my Arduino UNO without a hith for a few days now, but suddenly I can't program it anymore.</p>

<p>When I try to programm my Arduino on Mac, I get the following Error:</p>

<pre><code>avrdude: stk500_recv(): programmer is not responding
</code></pre>

<p>The USB option under serial port has disappeard (It was there before). Has anyone an idea on how to fix this?</p>

<p>The last thing I did is use the serial port for some communication. A reboot hasn't improved anything.</p>

<p>I tried programming Linux, but it resulted in the exact same result.</p>
 313: <p>If I try to upload with no device connected, I get a dialog with the message "port is blocked" and a message in Eclipse's console window that the port is not found.</p>

<p>So I'm guessing you've got a sync problem. UNO should reset automatically when avrdude connects. Try manually resetting it just before you click to start the download. If that works, then the automatic reset has failed.</p>
 2817: <p>It seemed to be a hardware problem on the board. Thanks for the effort.</p>
