Mac OS X is a computer operating system developed by Apple Inc. It is the successor to the original Mac OS, which had not been updated since 1998 when it was replaced with OS X in 2001. The current release of macOS is called Mac OS X Yosemite (10.10) and is available for free on many new Macintosh computers.
The history of Mac OS X can be divided into several different eras. The first era, called “Classic Mac OS”, ran from 1984 to 2001 and consisted of a series of different operating systems that were based on the original Mac OS. The second era, called “Mac OS X”, began in 2001 and is still ongoing. It has seen six different releases so far, with the latest being Yosemite (10.10).
Mac OS X is based on UNIX, a powerful operating system that is used by many large organizations and universities. UNIX is known for its stability and security, which is why Mac OS X is often chosen by businesses and governments. In addition to its stability and security, Mac OS X also provides a great user experience by making the computer easy to use and access.
Fix a corrupted Mac OS X
If you are experiencing problems with your Mac OS X installation, such as corruption or unexpected behavior, you may need to repair it. To do this, you will need to use the Terminal application.
First, make a backup of your files. This is important, as repairing your Mac OS X installation may erase all of your data.
Boot your Mac off of your Mac OS X DVD or Mac OS X Install Disc 1 (or whatever disc came with the machine).
Note: These instructions will not work if you are using a custom firmware such as Chameleon or rEFIt. If you have one of these, try searching Google for how to boot off of a DVD on your machine.
- Once the disc has booted, you will see a screen with a few options. Choose “Install Mac OS X.”
- You will be prompted to choose your language. Click the arrow next to the flag of the country where you are located, and then click “Continue.”
- On the next screen, you will be asked to agree to the license agreement. Click “Agree” and then click “Continue.”
- You will now see a screen that shows all of your available disks. Choose the disk on which your Mac OS X is installed (usually this will be called “Macintosh HD”) and click “Install.”
- After a few minutes, you will be asked to choose a disk to install the recovery system on. Choose any disk and click “Install.”
- The installation process will now begin. When it is finished, your Mac will restart and you will be prompted to enter your administrator password.
- Once you have entered your password, you will see a screen with a few options. Choose “Terminal.”
- In the Terminal window, type the following command and press enter: fsck –fy
- Type your administrator password and press enter.
- The disk verification process will begin. Wait for it to complete, and then reboot your Mac.
- You will see a prompt that says “<OS X name> could not be installed on <some_disk>. This disk does not have enough space available.” Click “OK” and choose your Mac OS X installation as the disk to install on (usually this is “Macintosh HD”).
- The installation process will now continue. Once it is finished, your Mac OS X should work properly again!
full-disk version
For most users, running fsck works without issues, but there are some limitations. The full-disk version (fsck -fy) can take several hours on large drives, such as a 500GB disk. It also needs a significant amount of free space. If your Mac’s drive is nearly full, the command may not run.
A more limited version of fsck (fsck -f) is available that does not require as much free space and does not have as long of a run time. However, it can only be used on partitions that are less than 1GB in size, which covers most people’s home directories.