Uno doesn't appear in Serial Port menu

System: OSX 10.8.4 Board: Arduino Uno R2 Software: Arduino 1.0.5 Sketch: Any basic example

Positive signs: - Green light still turns on - Holding reset button for 10s and releasing causes "L" light to flash - Device DOES appear in USB Prober as "Arduino Uno DFU"

Possible cause: - Was trying to get 150 2812B LED strip to work in combination with FastSPI_LED2 example sketch FirstLight. - Plugging and unplugging LED's while board was powered on - Some other coincidental reason

Problem: - The board does not appear in Tools >> Serial Port. Though again, it does appear in USB Prober.

Attempted solutions: - Disconnected everything - Restarted 3 times - Tried to uninstall Arduino software by deleting and reunzipping the original package. This clearly didn't work because all the settings and libraries were still there when I reopened it. - Tried on another Mac and it was also not recognized by Arduino software there but was seen in the system information as "Arduino Uno DFU" - Cried

newhero: USB Prober as "Arduino Uno DFU"

The ATmega8u2 has stopped working as a usb to serial device and needs to be reprogrammed

http://arduino.cc/en/Hacking/DFUProgramming8U2

Thanks James.

Followed directions from your link. Device still shows up as DFU.

Checked version: 0.00 Installed DFU Programmer Downloaded Arduino-usbserial-uno.hex Arduino IS an SMD so no soldering

Reset the 8u2: Here I have a problem because when I short the pins specified the serial port disappears for a moment but then reappears. Is this right or should it stay gone?

sudo dfu-programmer at90usb82 erase >> RX light turns on

HERE IS THE ERROR: sudo dfu-programmer at90usb82 flash Arduino-usbserial-uno.hex Error parsing the line. Something went wrong with creating the memory image.

reset command executes without error unplug and replug device still listed as Arduino Uno DFU

I have had a similar issue, but can get it working again by re-flashing the firmware onto the 8u2 chip. But then the 8u2 chip will just randomly get stuffed up again, and has to be re-flashed.

The fact that the arduino can so easily reset the the 8u2 chip is a bit disconcerting...

@James: Do you have any ideas as to what could be the cause of the 8u2 firmware getting corrupted so easily?

Board / OS Details: Board: Arduino Mega 2560 Rev1 IDE Version: 1.0.5 OS: OSX 10.7.5

I have several 8u2 and 16u2 boards, but never have problems with the chips.

It does seem like most who do have caused a short circuit or over voltage issue. That little guy seems rather susepctible to damage, though I can't explain why.