avrdude: stk500_getsync(): not in sync: resp=0x00

The chip in my arduino uno will work fine when I send it a sketch. If I disconnect and reconnect, the chip doesn't function and gives me 3 blinks - delay - 3 blinks - delay - repeat. Seems like the chip keeps rebooting. If I send it a new sketch, it will operate like normal again.

Anyone?