Reason for Existence

It started with a tweet.

SafeToUnplug is a tiny faceless background app that notifies you (via 10.8's Notification Center) when it's actually safe to unplug a newly-unmounted drive.

For some reason Finder (seen last on OS X 10.8.2) sometimes dismisses a volume's icon from it's UI while the system is still actively unmounting it. Unplugging a drive while it's busy flushing its buffers is a great way to corrupt data.

Installation

Compile it yourself or snag the precompiled binary.

I recommend you add it as a Login Item (System Preferences > Users & Groups > Current User > Login Items.

Disclaimer

I'm not sure if this app will even work. I'd imagine the Finder uses the same mechanism as this app uses to dismiss the volume's icon. But maybe not. So this is a shot in the dark. Let me know if it fails for you and maybe I can think of something else. Or Apple could, you know, fix their software.

Credits

I was alerted to this SafeToUnplug implementation technique by Peter Hosey. The code is mostly stolen from Ullrich Schaefer's Stackoverflow answer.

TODO?

• I'm running 10.8, so I just used Notification Center directly. If someone sends me a patch to use Growl instead and/or make SafeToUnplug run on earlier systems that would be swell.

• Disk Arbitration has DARegisterDiskDisappearedCallback. Looks lower-level. Should I use it instead of name:NSWorkspaceDidUnmountNotification?

Version History

v1.1: Fri Apr 12 2013

• Suppress unmount notifications of volumes named "Boot OS X".

  For some reason OS X like to mount and unmount this rescue volume a lot and it's annoying to be notified of it.

v1.0: Tue Oct 30 2012 download

• Initial release.