How to disconnect external drive

SmartWare would begin backing up new or updated files from my computer as soon as I connect external HDD using USB cable.  However, when you want to detach the external HDD, what is the best way to do it?  What happens if you simply disconnect USB cable from the external HDD while back up is in progress?  Would it result in damage to some data on the external HDD?  Similary, let’s say smartWare was backing up files to a NAS over the network, and while it was backing up, either computer crashed or network went down.  Is SmartWare able to handle situation like this?

That could corrupt your files, that’s why you need to safely eject the hard drive from the PC before you disconnect the USB cable. Check the link below for the steps.