Can't program Arduino UNO using Mac when circuit is connected

as title says. works fine when disconnect circuit (by unhooking earth), when if earth of circuit connected kind of stuff

quote

avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x00

i suspect what's happening circuit being connected somehow unbalancing bus, , it's shoddy mac implementation of usb ...

has seen issue before? i'd able reprogram board without having disconnect earth each time!

my circuit way  just simple led sequence connected each of output pins 0-9

serial upload uses serial pins: 0 , 1.  if connect hardware 2 pins interfere serial i/o.  try moving leds 2-11 instead of 0-9.

Arduino Forum > Using Arduino > Installation & Troubleshooting > Can't program Arduino UNO using Mac when circuit is connected

arduino