Watchfae works in Emulator but only works for a second and then shows a blank screen on watch. No errors the application works fine, it just does not display the the time on the watch.

Thank you for pointing me in the right direction. When I start something new sometimes I end up with an information overload and end up missing some key things. I did not know dc was not persistent on AMOLED devices.

I did know about the low power mode because that works well in the emulator and already tested it.

I tried to do a lot of optimisation and ended up wasting time for nothing.

I am handling low power mode and on the emulator it is working fine.

However on the device it is not working even though Always on is enabled settings->display->non activity-> screen timeout.

It works 10% of the time and I get a blank Screen 90% of the time. I am only drawing a digital watch in a small font that moves around. "View Heat Map" shows that it is safe and working correctly.

 // Terminate any active timers and prepare for slow updates.
    function onEnterSleep() as Void {
        lowPowerMode = true;
    }
    
    // The user has just looked at their watch. Timers and animations may be started here.
    function onExitSleep() as Void {
        lowPowerMode = false;
    }
    
    // Update the view
    function onUpdate(dc as Dc) as Void {
        if(lowPowerMode){
        }
        else {
        }
}

I resolved this issue from an Old answer you yourself posted. Thanks again jim_m_58.

The issue was not calling WatchUi.requestUpdate() onEnterSleep and not wearing the watch when testing. AMOLED displays turn off when not  worn not matter the settings.