The power supply has a LED light that glows orange when the Xbox is off and green when it is switched on. I turned off the Xbox 30 minutes ago and the power adapter is still green. Why is that?
I suspect that after a while it notices that there's little electricity and then switches to standby.
I thought so too, but it's been 45 minutes now and it's still green. The power supply is new, by the way, because it was the same with my old one and I thought it was broken.
The transformer in the power supply works like a small battery. Even if there's no more current flowing, there's still enough current stored to make the LED light up before it goes to sleep.
That sounds a lot like "instant on mode".
If your console is in instant-on mode, the LED on the power supply remains permanently on white or green, as it continues to draw power so that the console can be started up quickly and even switched on by voice command.
To check whether this mode is activated and to switch it off if necessary, proceed as follows:
Press the Xbox button to open the guide.
Select System (Small Gear Icon)> Settings> General> Power Mode & Start.
Change the setting using the Power Mode drop-down menu.
There you can choose between instant-on mode and energy-saving mode. The setting is then adopted directly.
You can read more about the differences here: https://beta.support.xbox.com/help/hardware-network/power/learn-about-power-modes.
I just tried it now. It was still glowing green for 2 minutes and I thought that this would not have been the mistake. Suddenly the LED is orange. So great.