I ran into the not-so-good error of “The device failed to calibrate the laser power level for this media” on my less than a year old MacBook Pro the other day and was not too happy. Being that I work in a Dell shop, I know that all their PC’s come with built in hardware diagnostics. I knew Apple had to include one on theirs as well, but where? It’s pretty simple really, power off your computer, and when you power it back on press and hold the D key on your keyboard and your Mac will enter diagnostic mode where it will test the hardware inside your lappy. See the screensnap below.