Yes, I believe I've found a workaround! I have had the very same problem with my G70 receiver. Tried updating the firmware from 1.03 to 1.05 on two Macs, a MacBook Pro and a MacBook Air. Reconnecting, power off and back on, restarting the Line6 updater app, performing a factory reset on the receiver etc. did not resolve the problem. I would receive the same error message every time. This morning I had access to a Windows laptop running Windows 7. After installing the V1.11 Line6 updater app I was able to update the firmware to V1.05 on my G70 receiver. Maybe the above described update problems are isolated to the Line6 updater app for Mac?