Xbox One X constantly spins up and down external hard drive whilst in instant-on mode.

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.

okay instant on mode is already off because that's your way to get it to work with external hard drive it's an energy mode right now. And I have to keep the x box on in order for it to download to that hard drive. So you're saying leave the instant on mode
off and keep it on energy mode, and try to download to the internal hard drive? if it works with the external hard drive then it should work with the internal hard drive doing it that way shouldn't it? Because it does work with the external hard drive with
it on energy mode

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.

If in instant-on mode the hard drive can be spinning to download updates and sync with the servers.

Also you shouldn't just yank the power cord especially if the hard drive is spinning as that will probably corrupt it.

If you want to disconnect power it is best to switch to power saving mode then switch it off so that it fully shuts down.

Is you Xbox on instant on mode? Of so the only way to get it to shut down is energy saving mode. The problem is the xbox checks for updates and various other things alot on instant on mode and has to spin up the external to do it.

support.xbox.com/.../learn-about-power-modes

If you xbox is on energy saving mode already then try a hard restart (hold power button until xbox is off, wait 30 seconds then turn it back on).