[FIXED] Was able to upload from Linux IDE, now can't

Okay, my first Uno (first Arduino, period!). Had a couple of weeks of happy learning. Then, a couple of days ago I started getting “Error opening serial port /dev/ttyACM0”. When I unplug and replug USB, it appeared that the next USB serial port was being selected (e.g. /dev/ttyACM1, 2, etc.). I would reselect the serial port in the IDE and try again, same error message. After the serial port failure the IDE no longer shows a ttyACMx serial port as available.

Tried removing (apt-get purge) everything, including the ~/.arduino directory, and reinstalling. Tried powering down the workstation. Nada.

Tried a clean install in my Ubuntu Linux laptop (both desktop and laptop are 10.10, by the way). Had a couple of successful uploads, then the same thing happened as with the desktop. Error opening serial port, no upload, incrementing USB ports.

Tried going to the board directly with avrdude. Errors reading from the board.

So, I dual-booted into Windows Vista, installed the USB driver and the Arduino IDE. Uploads working fine! Made some minor edits to Blink and BlinkNoDelay, still no problem. Installed a sketch that would exercise the serial port (ASCII Table) and that’s working fine.

So, did I prove the board is okay, or not? What am I missing? Is there some other debug process that I can try?

Using Ubuntu Linux 10.10
Arduino IDE maverick 022
Arduino Uno (surface mount)

I have been keeping up with updates on my Ubuntu systems, but I can’t recall seeing anything come in the past couple of days that might have effected this (but, hard to tell). I live in Mexico, so getting another Uno to test with right now isn’t an option!

Oh, and in case anyone asks, I have updated the 8U2 firmware.

Try rebooting the machine Running the arduino software as root Check what dmesg has logged when you plug in the usb cable do a lsusb (with the usb cable plugged in)

Post the result

Cool. Starting the IDE as root worked great. Got a message in the terminal that librxtx was removing a stale lock file - I guess left over from all the other testing I was doing.

So, I guess I had a permission or ownership issue, or something I installed along the way caused the issue.

I deleted my ~/.arduino folder, restarted as me and pointed the IDE to a new directory. Worked like a charm. So, something in my original sketch directory must have been causing the problem. There was a file named "FP6380SG0SD2Z09.tmp" in my old directory. I deleted it, moved back to the old directory, and everything started working.

So, either starting out with a new preferences.txt (which I've tried before) worked, or deleting that .tmp file did it. Either way, I'm back in business!

Thanks very much!