Generally if I&#x27;m worried about completing a write, I&#x27;ll just open a Terminal and type `sync` (with a `&amp;&amp; sudo purge` on OSX), and then, as soon as that returns, yank the drive.<p>I don&#x27;t even bother to unmount it; what would unmounting <i>add</i>, if the OS can recognize that the device is gone and clean up its mount tables? Is there some filesystem that waits until unmount to recalculate indexes or something?<p>(Okay, sure, the OS could tell me the disk is in use because I&#x27;ve got an overlay filesystem mounted on top of it, and would I kindly wait forever for that to stop being the case. But screw you, OS, I need this USB. Just send the FUSE server or SMB daemon or whatever a SIGPIPE.)