External HDD still spinning up/down constantly while console is off and instant-on is...

I keep my console set to Instant-on also and used to experience the constant spinning up and down of external drives also.

I believe the option that I changed to stop constant spin-up and down was by navigating to Settings/Power & Startup/Power Mode & Startup and unchecking "When Xbox is off, turn off storage."

The result will be that your external drives will spin when the console is standing by, but I think for my own purposes I'd rather have that than the wear and tear of the drives constantly spinning up and down.

There is an option in the settings, can't remember where to get the xbox to power down an external HDD when the console is of. I think it only works with HDD that don't have an external power supply.

If it is on with one with external power supply then I would say something is wrong as mine doesn't spin up while the Xbox is off unless it's downloading an update for a game.

Yes that seems like a possibility, i will try it and post what the results are.

On a side note, every time i turn my xbox one off, the external hdd spins down aswell. But then after a few seconds, the external disk spins up again. Only to spin down, and as soon as it has done that, it spins back up again. And so on so on like 8-12 times
before it finally spins down and stays in that state.

Also i have noticed that the external hdd spins up at random times, when the XBO is turned off. So i have assumed that the XBO did have control over it, even when in low power mode.

Especially since my external hdd uses its own power supply (which rules out not enough power from the XBO in low power mode to run it.)

But as mentioned above, i will try it and post the results

This is intended. The HDD will remain available to the console for when it loads up again. Otherwise the Xbox One would have to spin up the HDD which would lead to possible delays depending on the HDD which is against the Instant On idea of everything being
available straight away.

The other solution rather than unplugging the HDD it to set your console to actually power off rather than sit in Instant On mode.

What part of the HDD being on is the problem for you? Can you hear it spinning? Is it flashing access light etc? I use a My Passport HDD and it runs silent but flashes the access light intermittently to show it is still on.

I am also having this issue, but with a Seagate Backup Plus Hub 8TB.

If I use instant on mode, when the console is off the hard drive turns on, spins up, turns off, spins down and this cycle repeats every 30 seconds or so endlessly. None of the settings related to external hard drives, such as the option to turn off external
storage when the console is turned off, make any difference.

If I use energy saving mode, when the console is turned off the light on my external goes off, but the drive doesn't actually spin down. It continues to spin indefinitely until I pull the USB cable out of the console, then it will spin down.

Before the latest update, if I used instant on mode the hard drive would only spin up periodically when the console was checking for updates, or if it was downloading something. At all other times it would be off and spun down. If I used energy saving mode,
when I turned the console off, the hard drive would fully turn off and spin down and stay that way until the next time I turned the console on. I believe that these are the expected behaviours.

I have tried factory resets, using a different USB port on the console, using a different USB cable, and fully formatting the external and starting over. Nothing works.

The external works fine when connected to my PC. Also, I downloaded Seagate's SeaTools application and ran the tests that it offers on my external and it passed them all, so it appears to be in good shape. Given that I only started having issues after the
dashboard update and that it works fine on my Windows 10 PC, it makes me believe that something related to the update has triggered this issue.