How to Reboot an Apple iMac to Its Factory Settings

By G.S. Jackson

When using an iMac computer for any length of time, it tends to gather unnecessary programs, files and other junk that slows it down or makes it hard to maintain. One solution involves erasing the hard drive and reinstalling the operating system through the system restore utility. This effectively restores the iMac to its original factory settings. The system restore utility is accessible after rebooting the computer.

Click the Apple icon, and then click "Restart" from the drop-down menu.

Press "Command-R" when the screen goes dark. Continue holding until the recovery window appears.

Click the "Disk Utility" option, and then click "Continue" to open the Disk Utility window appears.

Select your main hard drive from the list of drives on the drive pane.

Click the "Erase" tab. Set the format to "Mac OS (Extended Journaled)" in the Format drop-down menu.

Click the "Erase" button. Wait for the process to complete, and then click "Quit." The main restore window appears.

Select "Reinstall Mac OS X <version>," where "<version>" is your OS X version name. The OS X reinstall window appears.

Click "Continue," then "Accept" to accept the OS X license agreement. The drive selection window appears.

Click the icon for your main hard drive that you just formatted, and then click "Install" to install a new operating system set to the original system settings.


Using the Disk Utility installs the current operating system to factory settings. For older versions or OS X, you need an installation disk.