When I get a problem uploading to my boards I have upload a different program like the blink example. This seems to reset something and I am then able to upload my own program (which is quite large).

It might be worth trying this to see if it works in your case, although I have no idea why it works.

When I get a problem uploading to my boards I upload a different program like the blink example. This seems to reset something and I am then able to upload my own program (which is quite large).

It might be worth trying this to see if it works in your case, although I have no idea why it works.

I have repeatedly had success by uploading a different simple program (eg Blink).

For me, this will always upload, and after Blink is on my own program will upload OK.

So my problem is something related to re-uploading over my own large program.

Worth a try for others if you've got this far down the answers and are still struggling (;

When I get a problem uploading to my boards I have upload a different program like the blink example. This seems to reset something and I am then able to upload my own program (which is quite large).

It might be worth trying this to see if it works in your case, although I have no idea why it works.