Mac OS X 10.4 Tiger was included with all new Macs, and was also available as an upgrade for existing Mac OS X users, or users of supported pre-Mac OS X systems. The server edition, Mac OS X Server 10.4, was also available for some Macintosh product lines. Six weeks after its official release, Apple had delivered 2 million copies of Mac OS X 10. Download Mac OS X Yosemite - The OS X Yosemite 10.10.5 update improves the stability, compatibility, and security of your Mac, and is recommended for all users. Find your OS X Yosemite installer in Applications. Eject the disk image that you'll see mounted on your desktop. Don't try to open the Yosemite installer from Applications and upgrade the Snow Leopard 10.6.8 drive. It's going to cause a kernel panic on the first reboot.

macOS Big Sur elevates the most advanced desktop operating system in the world to a new level of power and beauty. Experience Mac to the fullest with a refined new design. Enjoy the biggest Safari update ever. Discover new features for Maps and Messages. And get even more transparency around your privacy.

Check compatibility

macOS Big Sur is compatible with the following computers. If your Mac isn't compatible, you might be able to install an old version of macOS instead.

MacBook introduced in 2015 or later
MacBook Air introduced in 2013 or later
MacBook Pro introduced in late 2013 or later
Mac mini introduced in 2014 or later
iMac introduced in 2014 or later
iMac Pro
Mac Pro introduced in 2013 or later
View the complete list of compatible computers.

Mac Os X Yosemite Upgrade To El Capitan

If upgrading from macOS Sierra or later, your Mac needs 35.5GB of available storage to upgrade. If upgrading from an earlier release, your Mac needs up to 44.5GB of available storage. To upgrade from OS X Mountain Lion, first upgrade to OS X El Capitan, then upgrade to macOS Big Sur.

Download macOS Big Sur

If you're using macOS Mojave or later, get macOS Big Sur via Software Update: Choose Apple menu  > System Preferences, then click Software Update.

Or use this link to open the macOS Big Sur page on the App Store: Get macOS Big Sur. Then click the Get button or iCloud download icon.

Install macOS Big Sur

After downloading, the installer opens automatically. Click Continue and follow the onscreen instructions.

Please allow installation to complete without putting your Mac to sleep or closing its lid. During installation, it might restart and show a progress bar or blank screen several times. You might find it easiest to begin installation in the evening so that it can complete overnight, if needed.

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Mac Os Yosemite Review

After installing macOS Big Sur, you will be notified when updates to macOS Big Sur are available. To check for updates, choose Apple menu  > System Preferences, then click Software Update.