Special iMac Keys that Can Come In Handy
Several keys have special powers over your iMac. No joke! These keys affect how your computer starts up, and they can really come in handy while troubleshooting.
Using Safe Boot mode
You can use Safe Boot mode to force El Capitan to run a directory check of your boot drive and disable any login items that might be interfering with your system. Follow these steps:
- Choose the Shut Down menu item from the Apple menu to turn off your iMac.
- Press the Power button to restart the computer.
- Immediately after you hear the start-up tone, press and hold down the Shift key (and keep holding it down until you see the boot progress indicator).
- After El Capitan boots, you’re in Safe Boot mode, and you can check the operation of your iMac by using Disk Utility (or a commercial utility application). When you’re ready to return to normal operation, restart your iMac again (this time, without pressing the Shift key).
Here’s the lowdown on start-up keys. Hold down the indicated key either when you push the Power button or immediately after the screen goes blank during a restart. (The Shift key shortcut to Safe Mode is the exception; you should press it and hold it down after you hear the start-up tone.)
|Key||Effect on Your iMac|
|C||Boots from the CD or DVD that’s loaded in your optical drive (if you have one)|
|Media Eject||Ejects the CD or DVD in your optical drive (if you have one)|
|Option||Displays a system boot menu, allowing you to choose any bootable operating system on your iMac|
|Shift||Boots in Safe Mode|
|T||Starts your iMac in Target Disk mode (using your Thunderbolt or FireWire port)|
|⌘+V||Shows OS X Console messages|
|⌘+R||Boots from the El Capitan Recovery HD volume|
|⌘+S||Starts your iMac in Single User mode|
|⌘+Option+P+R||Resets Parameter RAM (PRAM)|
Some of the keys and combinations above might never be necessary for your machine, but an Apple technician might instruct you to use them.