by

Cannot Reinstall Os X El Capitan

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.

OS X El Capitan Installer. Official OS X El Capitan Installer from the Mac App Store. Un-archive the zip archive and you will get the app Installer. A bootable ISO or bootable USB can be made from this installer. Instructions on how to do that are on the Internet/Youtube. I created a USB disk with a bootable El Capitan as per this documentation. Plug-in your USB key on a turned-off computer. Start your Mac, press immediately OPTION (aka ALT) Select the Orange icon (aka a USB stick) labelled El Capitan. If it does not detect it after 10 sec and you only see your hard-drive. Try another USB port and wait 10 sec again. When it boots up it immediately goes to the OS X Utilities menu, with options to restore from a time machine backup, reinstall OS X, get help online, or open the disk utility. Since it's new for her and she has no data on it, I tried to click Reinstall OS X. Reinstall El Capitan. Now that the macOS Sierra has been erased from your drive, you will need to re-install the OS X El Capitan. Re-install OS X from OS X utilities and choose the OS X El Capitan Installer.once the process is complete, restart the Mac. Invoke Recovery mode while the Mac is starting up by pressing together the Command + R keys. As explained here, OS X 10.11 'El Capitan' fails to install because it is too old (the technical reason being that the signing certificate is no longer valid). But you can trick the OS X installer into thinking that it is 2017 and it will happily run without any errors. How to trick the OS X installer.

Check compatibility

Cannot

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.

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.

Why Can't I Reinstall Os X Yosemite

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.

Cannot Reinstall Os X El Capitan Download

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.

Cannot reinstall os x el capitan operating systemCannot reinstall os x el capitan os

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.

Can't Reinstall Mac Os X El Capitan

Stay up to date

Install El Capitan Os

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.