Arduiino Nano loses program on power re-connect

I have a bunch of Aduino Nano Boards all v3.3.

None of them seem to retain their programming after disconnecting power and then reconnecting power.

I have an Arduino Due that seems to be OK, any suggestions ?

None of them seem to retain their programming after disconnecting power and then reconnecting power.

Not even something simple like the Blink sketch ?
How are the boards being powered ?

It sounds like there is something at runtime which us not being satisfied... perhaps an EEPROM variable, or an input state that isn't there after the programming cycle / restart cycle...?

I highly doubt the code has disappeared, it's just not being accessed.

This a good reason to use the onboard or external LED as a CPU activity indicator... toggling the led each time around the main loop (using millis() not delay() !!!). You can tell at a glance if anything is happening - or blocked up.

UKHeliBob:
Not even something simple like the Blink sketch ?
How are the boards being powered ?

Boards are powered via USB and I tried a simple blink program but to no avail.

So what does happen if you upload the Blink program, let it run for a while with the LED blinking, disconnect the USB cable, wait a few seconds and reconnect it ?

Is anything connected to the Arduino pins ?