Put Hard Disk to sleep option disappeared

Restart in Safe Mode. This will perform a Disk Repair, clear cache files and only load Apple Software, extensions and fonts. The boot up will be slow and can take some time - Normal.

2 - Safe Mode will also eliminate Third Party Software, extensions and drivers from loading. It will only load the Minimum amount of Core Apple Processes to allow the the computer to function at a reduced Level of Performance 

3 - Does the issue present in this mode ?

4 - Sometimes a Safe Boot followed by a Normal Boot will just put things right.

I have the same problem.

Restarting does nothing and neither does booting up in safe mode, then restarting again.

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I hope you can help.

EruditeBirdy wrote:

Restarting does nothing and neither does booting up in safe mode, then restarting again.

I hope you can help.

Do you have an external drive connected and is it mounted?

The setting only appears when an external drive is connected.

Below will not bring back the UI configuration in System Setting.

Be certain of what you are doing when modifying the Normal Setting.

Terminal command is unforgiving especially when using pmset

Run the command below

man pmset

SETTINGS

     disksleep - disk spindown timer; replaces 'spindown' argument in 10.4

     (value in minutes, or 0 to disable)

dialabrain wrote:

Do you have an external drive connected and is it mounted?

The setting only appears when an external drive is connected.

Thanks for that. It is so annoying how Apple goes & hides so many settings like this or with holding the Option key for others to appear. Would be nice if they just renamed the setting to specify "external" and leave it there all the time. I miss the days when macOS actually made some sense. And yes, I can see what Apple is trying to do by hiding it, but how many people are going to go back there later on to check? It is like a game of whack-a-mole just to locate settings & options these days.

Try booting into Safe Mode then restart normally. Sometimes that will fix anomalies.

How to use safe mode on your Mac - Apple Support

Try restarting.

Same happened to me. Figured out that the option reappeared when I've plugged in external flash drive that wasn't plugged in when I've originally selected the option.

You're welcome. I tend to not fret over changes Apple makes. But that's me. 😎