Download: OS X El Capitan This will be downloaded as a disk image called InstallMacOSX.dmg. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, which has the name InstallMacOSX.pkg. It installs an app named Install OS X El Capitan into your Applications folder. Built right into OS X, OS X Recovery lets you repair disks or reinstall OS X without the need for a physical disc. The OS X Recovery Disk Assistant lets you create OS X Recovery on an external drive that has all of the same capabilities as the built-in OS X Recovery: reinstall Lion or Mountain Lion, repair the disk using Disk Utility, restore from a Time Machine backup, or browse the web with. Starting up Mac OS into Recovery Mode allows for various important troubleshooting and recovery features, including the ability to reinstall MacOS, repair a hard drive with Disk Utility, erase a boot disk, restore a Mac from a Time Machine backup, adjusting and setting Firmware passwords, as well as some other more advanced functionalities. Bootable USB Stick - macOS X Catalina 10.15 - Full OS Install, Reinstall, Recovery and Upgrade. Please CHECK twice if your Mac model is compatible with this macOS!! If you are not 100% sure please message me your mac model and year and I can tell for sure if would work or not!
Rachel is trying to sell her Mac, but…
Click Update to open the macOS installer, which you can use to reinstall macOS on the startup disk. Or click Startup Disk and choose a different startup disk, which your Mac will also attempt to verify. Windows: An alert informs you that you need to install windows with Boot Camp Assistant.
My friend was wiping my Mac so I could sell it and I’m pretty sure they’ve deleted the start up disk? It’s not letting me reinstall the OS on a recovery startup.
She wonders about a fix. There are a couple of options with an erased partition.
Because Recovery didn’t work, the fastest way to install fresh is to make or borrow a macOS installer on a USB flash drive or a disk drive. We have instructions for making a bootable installer with macOS Sierra (as well as archived versions for several previous releases). You need at least an 8GB flash drive. The article includes instructions on obtaining the installer, which might involve you having to use someone’s else Mac to download it, if you don’t have a replacement Mac on hand yet.
But if you can’t get access to another Mac or the necessary drive, it’s still possible to use a different Recovery mode on all recent Macs, dating back to 2010. Normally, you can start up a Mac while holding down Command-R to boot into what Apple now calls macOS Recovery. That allows you to run Disk Utility, reinstall or wipe and install the system, access Terminal for command-line functions, and so on. In that mode, when you choose to reinstall without erasing the drive, my recollection is that Recovery looks for the current OS system installer on your startup disk in the Applications folder, and uses that. (Apple doesn’t document that, and I haven’t had to test that for years.)
Failing finding it, Recovery downloads the currently installed version of macOS (or OS X), which is about 5GB. When complete, it installs it and reboots, and places the installer in the Applications folder.
Apple Recovery Disk Assistant Catalina
However, there’s yet another option: macOS Recovery over the Internet, which requires either a Mac model released in 2012 or later, or most 2010 and 2011 models with a firmware upgrade applied. There, the Mac reaches out over a Wi-Fi or ethernet connection to download the relatively modest Recovery software, which then bootstraps the download of the full macOS installer.
Apple says Internet-based Recovery should happen automatically on supported models, and you should see a spinning globe when that mode is invoked while the download occurs. However, if you have normal Recovery installed and it refuses to install macOS for some reason, you can manually invoke Internet Recovery.
While Command-R at startup always installs whatever the most recent version you installed on your Mac, holding down Command-Option-R brings down the very latest compatible version that can be installed. Apple also offers Shift-Command-Option-R, which installs the version of OS X or macOS with which your computer shipped, or the next oldest compatible system still available for download.
(Apple just changed this behavior with 10.12.4, but if you’re using Internet Recovery for a clean install on an erased drive, the new behavior should be active as it will be pulled from the version of Recovery that’s bootstrapped from Apple’s servers. The pre-10.12.4 option is simply Command-Option-R, but it acts like the new Shift-Command-Option-R, installing the shipped OS or the oldest compatible version.)
Apple recommends the Command-Option-R option as the only safe way to reinstall a Mac with El Capitan or earlier versions of macOS if you want to be sure your Apple ID doesn’t persist even after erasure.
Ask Mac 911
We’ve compiled a list of the questions we get asked most frequently along with answers and links to columns: read our super FAQ to see if your question is covered. If not, we’re always looking for new problems to solve! Email yours to mac911@macworld.com including screen captures as appropriate. Mac 911 can’t reply to—nor publish an answer to—every question, and we don’t provide direct troubleshooting advice.
These advanced steps are primarily for system administrators and people who are familiar with the command line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but it can be useful when you want to install it on multiple computers without having to download the installer each time.
What you need to create a bootable installer
- A USB flash drive or other secondary volume formatted as Mac OS Extended, with at least 14 GB of available storage
- A downloaded installer for macOS Big Sur, Catalina, Mojave, High Sierra or El Capitan
Download macOS
- Download: macOS Big Sur, macOS Catalina, macOS Mojave or macOS High Sierra
These will be downloaded to your Applications folder as an app called Install macOS [version name]. If the installer opens after download, quit it without continuing the installation. To get the correct installer, download from a Mac that is using macOS Sierra 10.12.5 or later, or El Capitan 10.11.6. For enterprise administrators, please download from Apple, not a locally hosted software update server. - Download: OS X El Capitan
This will be downloaded as a disk image called InstallMacOSX.dmg. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, which has the name InstallMacOSX.pkg. It installs an app named Install OS X El Capitan into your Applications folder. You will create the bootable installer from this app, not from the disk image or .pkg installer.
Use the 'createinstallmedia' command in Terminal
How To Use Recovery Disk Assistant Mac
- Connect the USB flash drive or other volume that you're using for the bootable installer.
- Open Terminal, which is in the Utilities folder of your Applications folder.
- Type or paste one of the following commands in Terminal. These assume that the installer is in your Applications folder and MyVolume is the name of the USB flash drive or other volume you're using. If it has a different name, replace
MyVolumein these commands with the name of your volume.
Big Sur:*
Catalina:*
Mojave:*
High Sierra:*
El Capitan:
* If your Mac is using macOS Sierra or earlier, include the --applicationpath argument and installer path, similar to the way this was done in the command for El Capitan.
After typing the command:
- Press Return to enter the command.
- When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
- When prompted, type
Yto confirm that you want to erase the volume, then press Return. Terminal displays the progress as the volume is being erased. - After the volume has been erased, you may see an alert stating that Terminal would like to access files on a removable volume. Click OK to allow the copy to proceed.
- When Terminal says it's finished, the volume will have the same name as the installer you downloaded, such as Install macOS Big Sur. You can now quit Terminal and eject the volume.
Use the bootable installer
Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:
Apple silicon
- Plug the bootable installer into a Mac that is connected to the Internet and compatible with the version of macOS you're installing.
- Turn on your Mac and continue to hold the power button until you see the startup options window, which shows your bootable volumes.
- Select the volume containing the bootable installer, then click Continue.
- When the macOS installer opens, follow the onscreen instructions.
Intel processor
- Plug the bootable installer into a Mac that is connected to the Internet and compatible with the version of macOS you're installing.
- Press and hold the Option (Alt) ⌥ key immediately after turning on or restarting your Mac.
- Release the Option key when you see a dark screen displaying your bootable volumes.
- Select the volume containing the bootable installer. Then click the up arrow or press Return.
If you can't start up from the bootable installer, make sure the External Boot setting in Startup Security Utility has been set to allow booting from external media. - Choose your language, if prompted.
- Select Install macOS (or Install OS X) from the Utilities window, then click Continue and follow the onscreen instructions.
Learn more
A bootable installer doesn't download macOS from the Internet, but it does require an Internet connection to get firmware and other information specific to the Mac model.
For information about the createinstallmedia command and the arguments you can use with it, make sure the macOS installer is in your Applications folder, then enter the appropriate path in Terminal: