Ubuntu AVR Dude Hanging During Upload to Leonardo

Hi,

I have a Leonardo that's working when I upload from my Mac, but not from an Ubuntu 16.10 machine. The Ubuntu machine can successfully upload to Uno and Pro Mini devices.

I'm trying to upload a variation of the standard Blink that has a different delay value. The IDE is finding the board as is "lsusb". When I attempt to upload, I get

avrdude: devcode selected: 0x44
avrdude: AVR device initialized and ready to accept instructions

Reading |

And the upload never progresses. Sometimes, I upload and get the following

avrdude: writing flash (4112 bytes):

Writing | ########################avrdude: error: programmer did not respond to command: set addr
###avrdude: error: programmer did not respond to command: set addr

Am I missing an Ubuntu package or other update?

Thanks in advance,
Carl