These advanced steps are primarily for system administrators and others 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 on multiple computers without downloading the installer each time.

What you need to create a bootable installer

File

Download macOS Catalina 10.15 ISO & DMG Image We hope that the information we have put together will be of use to you as you try to download this macOS. This OS is one of the finest that Apple has ever put out for the Mac and it is great fun to use. Go to the App Store, this can be found by going to the Apple Menu App Store or click the App Store icon in your dock. Once the App Store loads, type 'MacOS Catalina' into the search box in the top-left corner and press return and click the entry for Catalina to go to the download page. Click the 'Get' button.

  • A USB flash drive or other secondary volume formatted as Mac OS Extended, with at least 14GB of available storage
  • A downloaded installer for macOS Big Sur, Catalina, Mojave, High Sierra, or El Capitan

Download the latest Catalina Installer using the latest Catalina Patcher version. Some third-party applications do not open or crash on launch This is an issue Apple introduced in 10.15.4, and is not an issue with the patch itself. To work around this, immediately relaunch the affected application after receiving the crash message. According to Apple, each and everything is new and more advanced than macOS Mojave and macOS Catalina. Now macOS Big Sur is completely available on the App Store, in which you can download it freely. However, we will provide you the direct link for the macOS Big Sur DMG file which will help you in order to have a clean installation on Mac. Download: macOS Big Sur, macOS Catalina, macOS Mojave, or macOS High Sierra These download to your Applications folder as an app named Install macOS version name.If the installer opens after downloading, quit it without continuing installation.

Download macOS

  • Download: macOS Big Sur, macOS Catalina, macOS Mojave, or macOS High Sierra
    These download to your Applications folder as an app named Install macOS [version name]. If the installer opens after downloading, quit it without continuing 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. Enterprise administrators, please download from Apple, not a locally hosted software-update server.
  • Download: OS X El Capitan
    This downloads as a disk image named InstallMacOSX.dmg. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, named 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

Apple catalina dmg
  1. Connect the USB flash drive or other volume that you're using for the bootable installer.
  2. Open Terminal, which is in the Utilities folder of your Applications folder.
  3. 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 MyVolume in 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 is done in the command for El Capitan.


After typing the command:

Apple
  1. Press Return to enter the command.
  2. When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
  3. When prompted, type Y to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the volume is erased.
  4. After the volume is erased, you may see an alert that Terminal would like to access files on a removable volume. Click OK to allow the copy to proceed.
  5. When Terminal says that it's done, 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

Apple Catalina Dmg

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Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:

Apple silicon

  1. Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing.
  2. Turn on your Mac and continue to hold the power button until you see the startup options window, which shows your bootable volumes and a gear icon labled Options.
  3. Select the volume containing the bootable installer, then click Continue.
  4. When the macOS installer opens, follow the onscreen instructions.

How To Download Catalina Dmg

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  1. Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing.
  2. Press and hold the Option (Alt) ⌥ key immediately after turning on or restarting your Mac.
  3. Release the Option key when you see a dark screen showing your bootable volumes.
  4. 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 that the External Boot setting in Startup Security Utility is set to allow booting from external media.
  5. Choose your language, if prompted.
  6. Select Install macOS (or Install OS X) from the Utilities window, then click Continue and follow the onscreen instructions.
Catalina

Learn more

For more information about the createinstallmedia command and the arguments that you can use with it, make sure that the macOS installer is in your Applications folder, then enter the appropriate path in Terminal:

  • Big Sur: /Applications/Install macOS Big Sur.app/Contents/Resources/createinstallmedia
  • Catalina: /Applications/Install macOS Catalina.app/Contents/Resources/createinstallmedia
  • Mojave: /Applications/Install macOS Mojave.app/Contents/Resources/createinstallmedia
  • High Sierra: /Applications/Install macOS High Sierra.app/Contents/Resources/createinstallmedia
  • El Capitan: /Applications/Install OS X El Capitan.app/Contents/Resources/createinstallmedia

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.

Gatekeeper on macOS helps protect users from downloading and installing malicious software by checking for a Developer ID certificate from apps distributed outside the Mac App Store. Make sure to sign any apps, plug-ins, or installer packages that you distribute to let Gatekeeper know they’re safe to install. And now, you can give users even more confidence in your apps running on macOS Mojave by submitting them to Apple to be notarized.

Prepare for Distribution

A Developer ID certificate lets Gatekeeper verify that you’re a trusted developer when a user opens your app, plug-in, or installer package downloaded from outside the Mac App Store. Software signed with a Developer ID certificate can also take advantage of advanced capabilities such as CloudKit and Apple Push Notifications.

Generate your Developer ID certificate.

You can generate your Developer ID certificate in Xcode or in the Certificates, Identifiers & Profiles section of your developer account. Please note that you must be the Account Holder of your development team in the Apple Developer Program.

Sign and test your app.

Enable the hardened runtime capability and declare entitlements for the functions your app requires in Xcode. Archive your app and test the end-user experience of launching your Developer ID-signed app using a Gatekeeper-enabled Mac.

Xcode

To build your apps for macOS and submit them to be notarized by Apple, use Xcode 10 or later, available from the Mac App Store.

Get Your Software Notarized

Give users even more confidence in your software by submitting it to Apple to be notarized. The service automatically scans your Developer ID-signed software and performs security checks. When it’s ready to export for distribution, a ticket is attached to your software to let Gatekeeper know it’s been notarized.

For step-by-step details on uploading your Mac software to be notarized, read Notarizing Your App Before Distribution and the Xcode Help Guide.

Submitting with Xcode

Unpublished Software. It’s easy to get unpublished software notarized with the Export process or xcodebuild. Custom build workflows are supported by the xcrun altool command line tool for uploading, and you can use xcrun stapler to attach the ticket to the package.

Published Software. To submit software you’ve already published, upload it using the xcrun altool command line tool. Several file types are supported, including .zip, .pkg, and .dmg, so you can upload the same package you already distribute to users.

Viewing Upload Logs

In addition to checking for malicious software, the notary service catches common code signing problems that can prevent your software from installing properly. If notarization fails for your upload, check the status log for details.

Requirements

When users on macOS Mojave 10.14 or later first open a notarized app, installer package, or disk image, they’ll see a more streamlined Gatekeeper dialog and have confidence that it is not known malware.

Apple Catalina Dmg

Mac apps, installer packages, and kernel extensions that are signed with Developer ID must also be notarized by Apple in order to run by default on macOS Catalina.





⇐ ⇐ Catalina Unsupported Mac
⇒ ⇒ Os X 10.11 Download