I'm seeing a problem with a PC with 1.6.8 installed which does not happen on an older PC with 1.6.5.
Programs upload fine to the Nano and run fine the first time.
They also seem to be programmed OK to flash, if I power off and then power the board from a power supply, works fine.
If the 1.6.8 GUI is open however, and I plug the Nano into the PC to power it WITHOUT re-downloading the program, it never runs. The onboard LED blinks about once per second, which I assume is the bootloader.
Once I close the GUI, the program starts executing.
Any ideas?