Photon will not flash from Dev IDE

When I claimed my Photon, it was flashing orange so I got new keys using the CLI.

I can flash the Photon from the Build IDE no problem.

When I flash from the Dev IDE the LED flashes purple but the Photon does not restart. I waited about 5 mins and then hit the reset button but the old code was still running. I tried multiple times.

I tried in safe mode with the same result.

I flashed the same code to another Photon using the Dev IDE with no problem.

Can anyone help?
What else should I try?
Would the keys issue when I claimed the Photon have anything to do with it?

Thanks

Can you check if you actually had Latest (v0.4.7) targeted when you flashed your Photon from Web IDE?

If you haven’t got latest firmware on your device the default output of Dev will not run.

I did have the latest firmware flashed.

Having looked into it a bit more it seems to be caused by this line in my code “SYSTEM_THREAD(ENABLED);”