Why does my external hard drive keep spinning down and movies won't play on Mac mini?

I've had ongoing problems with my external drives after the computer wakes up from sleep. Try rebooting and see if the problems persist. I did full diagnostics over the phone with senior apple support and took it in to a local mac dealer (no apple store for 500 mi) where they also found no problems. They've ordered a new logic board and I'll update what happens but you are not alone. And I hope you'll post whether the reboot and no sleep fixes your problem.

Hi runekc,

I've had a similar issue with an external drive; the option to 'Put hard disks to sleep when possible' isn't available on the M4 Mac Mini running latest Sequoia OS. I did a bit of research and found this to be the solution. Working fine for me atm.

From the Terminal prompt:

sudo pmset -a disksleep 0

(https://iboysoft.com/howto/external-hard-drive-spins-up-down-constantly.html)

Hi kalianna,

I'm no unix expert, but it looks to me like the code is telling the system to change the pmset (power management timer set) to zero for (in my mind) all (-a) disks. Not sure what the -c would do. Perhaps someone else might know?

kalianna wrote:

Iʻve seen similar code posted on another thread with a "-c" instead of "-a". What is the difference? What is this code saying? If I have problems, what command reverses what this is doing? Iʻd like to try this but have some hesitation about writing code I find on the net. Thanks for your help.

From the pmset man pages:

man  pmset

SETTING

   pmset can modify the values of any of the power management settings defined below. You may specify one or more setting & value pairs on the command-line invocation of pmset. The -a, -b, -c, -u flags determine whether the settings apply to battery ( -b ), charger (wall power) ( -c ), UPS ( -u ) or all ( -a ).

If you think Full Computer Sleep Mode is causing an external drive to disconnect.

As a test:

Turn On "Prevent automatic sleeping when display is off"

Set "Turn display off when inactive" to 5 or 10 minutes

Leave the Mac Mini On and only allow the display(s) to turn Off

Do not manually Sleep from the Apple Drop Down menu

Shut Down the Mac when away for a day or more

It may get fixed, if enough folks send Feedback.

Feedback - Mac mini - Apple

Feedback - macOS - Apple

Is the WD drive connected to the Mac mini using a hub or dock...?

If so, by-pass the hub or dock and connect the WD drive directly to the Mac mini using a USB-C to USB-A adapter.

for some examples:

USB-C to USB Adapter - Apple

https://www.amazon.com/dp/B08Z768LCW/ref=sspa_dk_detail_1?

https://www.target.com/p/philips-usb-c-to-3-0-usb-a-female-adapter/-/A-79804275

Go to Apple > System Settings > Energy and make sure that "Put hard disks to sleep when possible" is Off.

If that doesn't help, then I would suspect that there is a compatibility issue or something is wrong with the WD.

Iʻve seen similar code posted on another thread with a "-c" instead of "-a". What is the difference? What is this code saying? If I have problems, what command reverses what this is doing? Iʻd like to try this but have some hesitation about writing code I find on the net. Thanks for your help.

Thank you both for your replies. Itʻs been so long since Iʻve used unix that I forgot about the man command. Iʻll try this tonight. I assume that if I want to revert back to its present state that I would do the same command with a 1 instead of 0, though I canʻt think of why Iʻd want to do that.