Your external hard drive spins down every few minutes, then stalls your Mac while it spins back up. SpinSteady keeps the drives you choose ready while you work, without keeping your Mac awake, and tells you if one slept anyway.
You unchecked "Put hard disks to sleep." You tried the Terminal commands. The drive still spins down. Here's the part Apple leaves out:
Keep-your-Mac-awake apps stop your whole computer from sleeping. SpinSteady only keeps the drive busy. Your Mac keeps its normal sleep settings, and when it wakes, SpinSteady checks your drives right away.
Every check is timed. If one takes as long as a spin-up, SpinSteady flags it, sends a notification, and suggests a fix, like a shorter interval or write mode.
The default read mode adds no writes to your drive and works on read-only volumes like Time Machine backups. If your enclosure only stays awake with writes, switch that drive to write mode.
SpinSteady has no networking code and no analytics. Nothing about you or your drives leaves your Mac.
Pick an external drive from the menu bar. SpinSteady keeps one tiny hidden file on it. Nothing else on the drive is touched.
A tiny read every 25 seconds (adjustable) keeps the drive's idle timer from running out. It keeps working through reboots, unplugging, renaming, and sleep and wake.
A green status for each drive, the timing of the last check, a running count of checks, and a notification if a drive sleeps anyway.
I built SpinSteady because my own external drives kept doing this to me for years. I tested it on the three USB hard drives on my desk: a WD easystore, a WD Elements, and a Seagate Expansion.
No subscription.
Because many external enclosures ignore that setting. They run their own idle timer in the drive or in the USB or Thunderbolt bridge firmware, and macOS has no supported way to change it. SpinSteady works around it by keeping the drive lightly busy so that timer doesn't run out.
No. SpinSteady only keeps the drives you choose busy. Your display and your Mac follow their normal sleep settings. While your Mac is asleep, nothing can touch the drives, so SpinSteady checks them as soon as it wakes. One honest note: a drive that keeps spinning uses a bit more power, which matters most for a bus-powered drive on a laptop running on battery.
It's a single small folder holding one tiny file, the one SpinSteady reads on a timer. That's the entire footprint. If you remove the drive from SpinSteady, you can delete the folder.
Read mode, the default, adds no writes. A drive that stays spinning does add running hours. Many people find that a fair trade against spinning up and down dozens of times a day, but it's your call, and you can turn SpinSteady off for any drive. Write mode, for enclosures that only stay awake with writes, writes a few bytes per check.
No. SpinSteady contains no networking code. Nothing is collected, nothing is transmitted, there are no analytics.
The unlock is a one-time App Store purchase, so refunds are handled by Apple through reportaproblem.apple.com.