I have an SSD boot drive (ADATA SP550) and a HDD (WDC WD6400AAKS-41H2B0) that has a previous installation of Windows 10 that I'm using the user directories and some programs from (Steam, for example.) The HDD is supposed to be a working backup that I can roll back to just by removing the SSD if need be, but with all user files being stored where they belong in the HDD even while using the SSD.

In order to get everything working correctly, I've had to change security settings to allow a non-administrator account to have access to their user folders (Documents, Downloads, Desktop, etc.) however changing security of any large enough chunk of the user folders leads to both the SSD and HDD locking up (100% disk usage, no transmitted data) for longer and longer periods of time until there's 1 minute locks with 1 second gaps between them, the only way to fix it is to abort changing permissions...

This isn't exclusive to changing security settings, but this is the best example that is the easiest to reproduce, in this use case, the SSD usage 100%, while the HDD usage is around 0-15% throughout until the drives lock up.

  • If you have them both on the same controller if you saturate it, you won't be able to do stuff. What other scenarios do you have where you encounter this? Does the process eventually finish?
    – Seth
    Commented Jun 10, 2017 at 11:24
  • The cycle continues for as long as it takes to complete or cancel the task, if the task takes too long (say, a 10GB file transfer, it'll take hours of cycling between states, it might never finish, I've never left it running for that long in fear of damaging the drives) Commented Jun 11, 2017 at 3:38
  • Just as I was writing this, something new happened, I hear the HDD spin down (as usual when it starts cycling) and now it's not listed in Task Manager, File Manager or Device Manager. Here's to hoping it'll come back with a reboot. I'll also use the SATA cable from the CD drive. Commented Jun 11, 2017 at 3:40

1 Answer 1


It appears that this was an instance of SATA saturation, this particular controller couldn't handle a SSD and a HDD plugged into the same controller, moving the SSD to a different controller fixed the issue for me.

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