When you are in recovery mode, click Reinstall macOS and then click continue.When the Apple logo appears, release the command and R keys. Keep holding them down until you see the Apple logo appear on your screen. As your computer is restarting, hold down the Command + R keys.You can do this by holding down the power button or by clicking the Apple logo by the top left corner of the screen and selecting Restart. Note: Your Mac needs to be connected to the internet to install or reinstall macOS. Follow the steps below to get a new version of your operating system: Using the Recovery Mode is an easy way to reinstall your Mac OS. How to Reinstall Mac OS Using Recovery Mode Warning: Make sure you do a full backup of your files before you reinstall your operating system. Here’s how to reinstall your Mac operating system(OS). This process is actually straightforward and simple. After the installation process completes, your iMac will automatically reboot into OS X Mountain Lion.Has your Mac computer been running into issues lately? It might be time to give it a fresh OS (operating system) installation. For example, choose the hard drive you want to reinstall the operating system on and enter your Apple ID and password when prompted. The OS X Utilities window re-appears.Ĭhoose 'Reinstall OS X' and click 'Continue.' Follow the directions to reinstall OS X Mountain Lion. Open the 'Disk Utility' menu and choose 'Quit Disk Utility' after the system displays the message that the disk has been successfully erased. The time for the process to complete depends on the amount of data on the disk. Click the 'Erase' tab.Ĭlick the 'Format' pop-up list and select 'Mac OS Extended (Journaled).' Enter a name for the hard drive in the Name box and click 'Erase.' The system automatically erases the disk. If you only have one hard drive, it will be the only disk available. If the system does not automatically connect to the Internet, select your wireless network from the Wi-Fi menu to establish a connection.Ĭhoose 'Disk Utility' from the list of options to open the Disk Utility window and click 'Continue.'Ĭhoose the hard drive you want to clear. Release the keys after the OS X Utilities window opens. Press the 'R' and 'Command' keys simultaneously and hold them when the system restarts.

Os x utilities menu