First hi,
10 minutes ago, my arduino worked fine and I have uploaded an sketch.
And now, it says me "avrdude: stk500_getsync(): not in sync: resp=0xfe" and won't upload my sketch...
Does anyone has the solution please? Thanks.
EDIT 1:
Oh, and, it's an Arduino UNO, and I'm programming it on an iMac.
Does the PC see the new USB connection when you plug the board into the PC?
If so next step is to perform a loopback test to see if the serial communications link is functioning.
Lefty
retrolefty:
Does the PC see the new USB connection when you plug the board into the PC?
It does.
retrolefty:
If so next step is to perform a loopback test to see if the serial communications link is functioning.Lefty
Already did it, it passes.
But thanks for the answer 
I don't know what hapenned to my UNO, but now, it says to me "avrdude: stk500_recv(): programmer is not responding" and not the "avrdude: stk500_getsync(): not in sync: resp=0xfe" that I had before...
EDIT 1:
I've rebooted the Arduino IDE and then it says me "avrdude: stk500_getsync(): not in sync: resp=0x30"...
This is SOO strange!! I hope anyone can help me raising this problem, cause it's my alone Arduino card...
I think I'm dreaming: my problem's auto-solved!!! No more error message! I'm so confused...