St. Clair Software’s Jettison ($2) is one of those apps that offers a feature you’d think would already be baked into OS X, but is missing for one reason or another. In this case, it’s automatic ejection of external disks.
If you close the lid on your MacBook and unplug your drives, you’re going to see the “disk was not ejected properly” dialog box when you open it back up, suggesting that your files may have been damaged in the process. Jettison is smart enough to automatically eject all of the external drives you have attached when you put your Mac to sleep, letting you pick up and go without worrying about corrupted files.
The app lives in your Menu Bar and provides quick access to actions such as ejecting external discs and putting your computer to sleep.
It provides the option of playing a variety of sounds to let you know when it’s safe to unplug the drives, which is a nice touch. Jettison even works to safely disconnect Time Machine backup drives and file server volumes. We wouldn’t be surprised to see Apple incorporate something like this in the future, but for now it could very well be worth the $2 if you’re constantly plugging and unplugging devices and drives.