I’m using M1X MacBook Pro 16 inch (2021) running macOS Monterey 12.3.1 with 4-bay hardware RAID enclosure from QNAP (TR-004) holding four 10TB Toshiba HDDs. The enclosure spins down the HDDs soon after they become inactive and I’d like to have them spinning all the time (granular control is desired, though; e.g. spin during the day, spin down at night).

Although I unchecked “Put hard drives to sleep when it’s possible” (wording may slightly be different) for both Battery and Power Adapter menu on the system preferences, the enclosure still spins them down.

Until a few weeks ago, having those options unchecked had been working. I believe software (most likely macOS) is to be blamed for this malfunction.

Does anybody know how to keep them spinning or how spinning/spin-down work on macOS? Is this controlled by S.M.A.R.T. or something else? If any of you happen to know an app that has granular control over HDDs’ behavior? Thank you in advance!

2 Answers 2


I’ve just solved my issue by myself. This turned out to be seemingly a macOS glitch. It sometimes messes up with the controls over external HDDs. Just unplugging/plugging and rebooting fixed this issue. Thank you.

Reference: https://www.stellarinfo.com/blog/resolve-mac-external-hard-drive-sleep-problem/#Third_Point_Header


In this case, the QNAP is controlling the drives, not macOS. You need to go into QTS and set the appropriate settings to disable Standby mode.

The device can be run via firmware, in which case here are DIP switches to control the RAID mode, or via a Mac App (QNAP External RAID Manager). For the firmware, the user guide says that there is a default Standby Mode:

*"The RAID enclosure features standby mode to help reduce noise and power consumption. When the RAID enclosure enters standby mode, the system fan and installed HDDs stop spinning, and system processes are paused. Upon waking, the RAID enclosure returns to the previous system state and any paused processes are resumed. The RAID enclosure enters standby mode under the following conditions:

  • The host enters hibernation or standby mode or is powered off. The RAID enclosure only enters standby mode if the USB power design of the host supports this feature.
  • The USB cable is disconnected."*

Perhaps there has been some other change that changes the way the QNAP 'sees' the Mac USB port? You might try the RAID Manager, see if that gives you additional options. Good Luck.

  • Thank you for your answer. Actually, my QNAP is just a hardware RAID enclosure, not a network drive or NAS. macOS see it as just one of external volumes and the OS doesn’t recognize four individual drives. As the enclosure behaves as a single volume and doesn’t have an OS like you mentioned (QTS), I’m still not sure what caused this automatic spooning down. Let me know your thoughts!
    – Hiroshi728
    Apr 1 at 17:26
  • macOS is not combining them into one volume - so there is some software running on the QNAP
    – mmmmmm
    Apr 1 at 19:33
  • It was kept spinning at least until recently and macOS has undergone two updates since then. I’m sure some kind of operating system is running on the QNAP enclosure (it’s surely not powerful enough to be called OS and to run NAS on it), but I still assume macOS is to blamed as those macOS updates seemed to have disabled the always-on-HDD mechanism.
    – Hiroshi728
    Apr 3 at 1:27

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