Not sure if this is a software Windows!! problem. But last year I got a Sparki robot this was based on the 32U4 controller and it worked fine for a few days, then I just couldn’t upload any code to it. I had installed all the right drivers, boards, etc.
Now I have my NEW Zumo 3204Oled robot and the same has happened again!! The code compiles OK but then I try to upload the code I get a message saying I don’t have access to the com port (USB/COM) Access denided!!! or programmer not found. I am the only user of this PC, Again think I’ve got the drivers right, etc.
Have you tried to push the reset button before uploading?
The upload procedure of a ATmega32U4 based Arduino board is much more complicated than on other boards. First the serial port is opened using a special configuration and immediately closed again. The board then resets itself to start in programming mode (bootloader). That reset lets the PC unload the driver just to be loaded again. If the PC doesn't do that in the time the Arduino IDE gives it for that, it might present the port in a wrong state.
Often the upload succeeds after a few tries but that isn't guaranteed. But it's usually a problem of the connected PC and not the Arduino board.
Hi to you both,
Many thanks for your replies, yes a download reset did the job.
The Pololu site suggested hitting the reset a couple of time when "Compile" becomes "Uploading" to took a few tries but worked OK and I am back on track to writing some code to get this doing something..