Writing to hard drive

[aay]

But don't forget, you have to mount the partition first! (Same method - right-click on it, select "mount" from the context menu.) You can tell a partition is mounted when a little green "power on" triangle in the lower right corner of its icon appears.

- e2g

That's certainly true. I just assumed he had already clicked on the icon and that the drive had been automatically mounted: bad assumption though.