We're intelligent creatures. We know the basics for using our iMacs, and we can most definitely figure out how to eject a disk. If you're old-school Mac, you know you can drag the icon to the trash can, although that often instills momentary fear thinking, "I don't want to destroy that!" Then there are the basic options of clicking the little eject button beside the disk name in Finder, or right clicking on the icon and selecting "Eject". And for those of us that never even thought to look, the full-size keyboard for the iMac comes with an eject button in the upper right above the Delete key.
But like I mentioned, we're all intelligent creatures, and you didn't need me to point those out. Besides, you can find other solutions on Google. The one problem is they almost all rely on your iMac recognizing the DVD in the first place. What do you do when your iMac is being stubborn and won't recognize the DVD, and won't eject it either? You can reboot your system holding down the mouse button, but most of us don't really want to reboot. Here's a handy little one I just found. Open up Terminal (it's found in the Utilities folder in your Applications), then enter "drutil eject". Happy iMac-ing...


