It's somewhat of a known issue: the reset sequence of devboards is dependent on the timings of the DTR/RTS sequence to reset the chip into bootloader mode, and those timings are dependent on a whole host of things (like PC hardware, OS, drivers, virtualization, ...). If you want to fix it: sometime...

Hi All, I have a strange issue during the Upload process when using the Arduino IDE. The connection process times-out around 70% of upload attempts on a secondary PC. The reason why I say that this is strange is that the exact same board upload almost immediately on my main PC with no timeouts or 10...