If you’re a Mac user with external disk drives that you use to clone your Mac, backup files, or to run Time Machine, then you know what happens when one of those drives falls asleep before you click an Open… or Save… dialog box button.
Spinning beach ball. Or, those dialog boxes take forever to open while your Mac waits for the external disk drive to spin up from a long slumber. Most of us own Mac notebooks, but the problem occurs with almost any Mac user with connected external hard disk drives. They seem to go to sleep when you need them the most, and OS X’s Energy Saver System Preference usually doesn’t help.
Yes, Virginia, there is a solution and it’s surprisingly simple.
It’s called Disksomnia; a clever Mac app which keeps those slumbering Mac disk drives awake, even if they want to sleep, or are scheduled to sleep. It’s like giving a disk insomnia. It may want to sleep, but it cannot.
Disksomnia writes a small file to the aforementioned Mac external disk drives every x-number of seconds. That keeps the disk from falling asleep and spinning down.
Open Disksomnia on your Mac. Click the plus + sign select which disk drives you want the app to keep awake. Adjust the number of seconds as needed (55 is default and that works well).
The app works in the background and every 55 seconds it writes a small file to the disk drive and that keeps it awake. If there are times when you want the disk drives to sleep, Disksomnia comes with an option avoid Always On and will only work when specific Mac apps are being used.
Preferences couldn’t be much more self explanatory.
Just select the external disk drive that you want to prevent from sleeping, and Disksomnia does the rest. I keep a few portable USB disks connected to my Mac for back and file transfer and this keeps them from sleeping, which keeps them from slowing down the pop up dialog boxes.
The default setting is for 55 seconds, which works in most cases; few Mac external disks will fall asleep in under a minute, but you can change the setting.
The Disksomnia Menubar icon displays the number of seconds until the next disk write. Simply put, Disksomnia works; simply. It’s not free but if you need those disks to stay away this is the one that works best.