If you're having trouble with your hard drive and need to boot your Mac from a different drive or disc, hold down the Option key during startup to open the Startup Manager, which will enable you to select a different volume. This should eject your disc while your Mac starts up. If you have a disc in your drive that is refusing to eject, restart your computer and hold down the mouse button as soon as you hear the startup chime. Of course, safe Boot Mode also enables you to make changes to prevent problems when booting your Mac in the future. This is normally exhibited by the startup hanging at the default grey screen, preventing OS X from booting.īy launching into Safe Boot Mode via holding down the Shift key during startup, your Mac forces a directory check of the startup volume and only launches the bare minimum of kernel extensions, fonts and startup items required, so as to avoid any that may be causing problems and allow for easier identification.

Safe Boot Mode is often the only way to boot into Mac OS X if the boot drive is encountering problems. Now the PRAM or NVRAM will have been reset and you can release the keys. If done correctly, your Mac will restart and you'll hear the chime again. In order to reset the values, hold down Command+Option+P+R as soon as you hear the startup chime. Resetting the NVRAM or PRAM can fix a number of Mac problems including startup issues.

The acronym-suited mouthfuls Parameter Random Access Memory and Non-volatile Random Access Memory refer to special stores of information for Mac OS X such as time-zone settings, startup volume, speaker volume, DVD region settings and more. This information can then be provided to tech support for advice on replacements and fixes. The Apple Hardware Test enables you to scan your discs and drives as well as other components to detect any problems with your computer's hardware.

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