Most external hard drives now days have an auto-sleep feature, which puts the hard disk to sleep after period of inactivity (e.g. 15-20 minutes).
While this has obvious advantages, sometimes you may not want this to happen – especially if hard drive has trouble waking up (like one of my drives).
NoSleepHD is a freeware utility that will stop your external drive(s) going to sleep. It works on a very simple principle – every few minutes (defined by user) it writes an empty text file to your drive(s).
It is very simple to use – once started, select which external hard drives you want to monitor, set the write timer interval, click on start and that’s it.
You can also set the app to start on every system startup.