Os Catalina Bootable Usb

Here's how to create macOS Catalina 10.15 bootable USB flash drive installer for a clean install on your Mac. With macOS Catalina being Apple's latest software release, it stands to reason that there is going to be a big interest in it.

I purchased a used 2018 Mac mini desktop and wanted to put a fresh installation of the latest macOS 10.15 Catalina on it. Below are the steps I took.

Make sure the USB drive is connected to the Mac. Next, click on the Apple logo from the top left and choose Restart. When you hear the startup sound or see the Apple logo, immediately press and hold the Option key. Select the bootable installer as the startup disk, and follow the instructions. How to Create macOS Catalina Bootable USB Flash Drive Installer Using Terminal Here’s how to create macOS Catalina 10.15 bootable USB flash drive installer for a clean install on your Mac. With macOS Catalina being Apple’s latest software release, it stands to reason that there is going to be a big interest in it.

Note: The instructions below are the same for macOS 10.13 High Sierra and macOS 10.14 Mojave.

Download macOS Catalina

You will need a Mac to download macOS Catalina; you can download Catalina from The Mac Go. (The Mac mini came with macOS 10.14 Mojave so I used it to download Catalina.)

Go to the Mac App Store, search for “macOS Catalina”, and download it. It will be saved to the “/Applications/Install macOS Catalina” location. If the installer automatically launches, just close it.

Note: If you plan to run the installer first to update your current macOS version to Catalina, you will want to move the “Install macOS Catalina” application out of the “/Applications” directory; otherwise, the installer will delete itself from the “/Applications” directory when the upgrade completes. For example, you can move the “Install macOS Catalina” application to the “~/Downloads” directory and run it from there.

Format USB Flash Drive

Because macOS Catalina is 8.4GB in size, you will need a 16GB USB flash drive. You don’t need to delete the existing content on the drive because we will blow it all away in a subsequent step.

If the USB flash drive is not already formatted as “Mac OS Extended (Journaled)”, format it like so:

  1. Plug the USB flash drive into your Mac.
  2. Launch the “Disk Utility” application.
  3. On the left-hand pane, select the USB drive (not the partition under it, if any).
  4. Click on the “Erase” tab (or button at the top).
    1. Input a name like “Catalina” (this name will be overwritten later).
    2. Select “Mac OS Extended (Journaled)” for “Format”.
    3. If available, select “Master Boot Record” for “Scheme”.
    4. Click the “Erase” button at the bottom. Click the “Erase” button in the warning popup dialog if you get one.
  5. The format operation may take several minutes to complete. (USB 2.0 and large capacity drives may take longer.) After the format completes, the partition will be mounted under “/Volumes/Catalina” (or whatever name you selected above).
  6. Close the “Disk Utility” application.

Write macOS Catalina to USB Flash Drive

To create a bootable USB macOS Catalina installer, run the “Terminal” application and this command:

# The --volume value is the mounted USB flash drive partition; in this case, named /Volumes/Catalina
sudo/Applications/Install macOS Catalina.app/Contents/Resources/createinstallmedia --volume/Volumes/Catalina
# You will be prompted for your user's administrative password.

Note: If the createinstallmedia command returns a “Failed to start erase of disk due to error (-9999, 0)” error, then your current Mac OS X version does not fully support the createinstallmedia tool. Use a more recent macOS version (at least Mac OS X 10.11 El Capitan) or manually create the USB installation drive using instructions from Bootable USB Flash Drive to Install Mac OS X 10.10 Yosemite.

Os Catalina Bootable Usb

The “createinstallmedia” program will erase the USB flash drive, create a new partition named “Install macOS Catalina”, and copy the installation files to that partition. The output will look like:

Erasing disk: 0%... 10%... 20%... 30%... 100%
Copying to disk: 0%... 10%... 20%... 30%... 40%... 50%... 60%... 70%... 80%... 90%... 100%
Making disk bootable...
Copying boot files...
Install media now available at '/Volumes/Install macOS Catalina'

The above process took 20-30 minutes using my Kingston USB 2.0 flash drive.

Boot From USB Flash Drive

Note: Apple’s How to create a bootable installer for macOS page suggest using the “Startup Disk” configuration (under “System Preferences”) to select the USB flash drive as the startup drive. Then on restart, the Mac should boot from the USB flash drive. Unfortunately, the “Startup Disk” did not list my USB flash drive as a startup option, so I was not able to use this method.

To boot a Mac with the USB flash drive:

  1. Insert the USB flash drive.
  2. While holding the “option” key down, turn on the Mac to display the Startup Manager.
  3. You should see one or more icons, one of which should be called “Install macOS Catalina” for the USB flash drive. (The internal hard drive may not be visible if it does not have a valid, bootable partition installed.)
    • Note: If you don’t see the USB flash drive’s “Install macOS Catalina”, try removing and re-inserting the USB flash drive while viewing the Startup Manager screen. The USB flash drive should then appear after a few seconds.
  4. Select the “Install macOS Catalina” (with left/right arrow keys) and hit the “return/enter” key to boot from the USB flash drive.

It may take 5-10 minutes to load the installer from the USB flash drive. Sometimes the progress bar may appear to be frozen or the screen will go black for a minute or two. Be patient.

Os Catalina Bootable Usb

External Startup Disk Not Allowed

On a newer Mac with the T2 security chip, booting from an external drive may be disallowed by default. Attempting to boot from a USB flash drive will result in a “Security settings do not allow this Mac to use an external startup disk” warning message.

To allow booting from the USB flash drive, do the following:

  1. Hold down “Command-R” (hold down both the “Command ⌘” and “R” keys) when you start the Mac to launch macOS Recovery. You can release the keys when you see the Apple logo.
    • Tip: An easier alternative is to hold the “Option/Alt” key on boot to launch the Startup Manager. Then just click and release “Command-R” keys to launch macOS Recovery.
  2. The macOS Recovery screen contains a top-level “macOS Utilities” menu.
  3. Click on the “Utilities” menu and select “Startup Security Utility”. Input your administrator password when prompted.
  4. In the Startup Security Utility, under “Allowed Boot Media”, select the “Allow booting from external or removable media” option.
  5. If the Mac won’t have access to the Internet (either by wire or wirelessly) when installing macOS Catalina, make sure to select either the “Medium Security” or “No Security” option under the “Secure Boot” section. (You can change the option back to the default “Full Security” afterwards.)
  6. Quit the macOS Utilities to restart the Mac.
  7. On restart, follow the directions in the previous section to boot from the USB flash drive.

Erase the Internal Hard Drive

When the installer finishes loading, you will see a “macOS Utilities” screen appear. It looks the same as the “macOS Recovery” screen with one difference. In the “macOS Utilities” window, the second option will say “Install macOS” instead of “Reinstall macOS”. In “macOS Recovery”, the “Reinstall macOS” option would just re-install the same version of macOS. The “Install macoS” option will install the macOS Catalina version on the USB flash drive.

Before installing macOS, I wanted a clean slate so I erased the internal hard drive like so:

  1. Select the “Disk Utility” option and click the “Continue” button on the bottom to launch the “Disk Utility” application.
  2. On the left-hand pane, select the internal hard drive (not the partition under it, if any).
  3. Click on the “Erase” button at the top.
    1. Keep the default “Macintosh HD” name or input a new one.
    2. Select “APFS” for “Format”.
    3. Click the “Erase” button at the bottom. The SSD (Solid State Drive) format took less than a minute to complete.
  4. Close the “Disk Utility” application.

Install macOS Catalina

Warning: If your Mac has a T2 security chip and you left the “Full Security” option configured in the Startup Security Utility, make sure that Internet access (wired or wireless) is available before starting the macOS Catalina installation. You can configure the wireless network by clicking on the wireless icon at the top-right corner of the macOS Utilities screen.

Usb

Back at the “macOS Utilities” window, do the following to start the macOS Catalina installation:

Os Catalina Bootable Usb
  1. Click on the “Install macOS” option and click the “Continue” button.
  2. The “macOS Catalina” installer’s splash screen will appear. Click the “Continue” button.
  3. Click on the “Agree” button to agree to the license. A popup confirmation window will appear; click on the popup’s “Agree” button.
  4. Select the internal hard drive and click the “Install” button.

My Mac mini took 20-30 minutes to complete the macOS Catalina installation. I think there were a couple of reboots in-between. And a few times, the screen would go black for a minute or two. Be patient and give the process an hour or more to complete.

If you run into problems installing macOS Catalina, check the “What Does Giving Up Mean?” section (at the bottom) of Install macOS Sierra Using Bootable USB Flash Drive for possible solutions.

Note: macOS Catalina seems to have an issue with my Dell 24in U2410 monitor. During the initial bootup screen, the monitor shows a blank screen with a message, “The current input timing is not supported by the monitor display”. Thankfully, the monitor works correctly after the bootup completes. And later, this warning message no longer appeared on bootup.

Enjoy your fresh installation of macOS 10.15 Catalina.


MacOS Catalina, macOS Mojave, and macOS High Sierra download directly to your Applications folder as an app named Install macOS Catalina, Install macOS Mojave, or Install macOS High Sierra. If the installer opens after downloading, quit it without continuing installation. Hint: before reading the guide (How to Install macOS Catalina On VirtualBox On Windows), it is suggested to browse into the necessary File part of the article and get macOS Catalina 10.15 then, and you will have time to browse the post before downloading has finished. When you are downloading macOS Catalina Virtual Machine image file and Google Drive touches its download limit, then right-click on the file and choose COPY to make a copy in the Google Drive of your own. From here download the macOS Catalina virtual image file. Moreover, we have provided an alternative link of media fire too. MacOS Catalina 10.15.4 introduces iCloud Drive folder sharing, Screen Time communications limits, Apple Music time-synced lyrics view, and more. The update also improves the stability, reliability.

macOS Catalina 10.15 is the latest operating system that runs on Apple Mac laptops and desktops. However, it is still in beta test and only available for part of Mac computers with high profile or enrolled in Apple Beta Program. Is there any way to upgrade the macOS to Catalina manually or install Catalina on Mac from scratch? The answer is Yes. But you have to download macOS Cataina DMG or the installer app.

If you are looking for the easiest way to download macOS Catalina DMG on a Macand but don't know how? Well, there are three ways by which you can instantly get the latest macOS installer without a hassle.

Part 1. Get MacOS Catalina DMG Via Direct Download Link

Many people prefer the direct download link of macOS Catalina as it is more flexible. You can unpack the DMG file and make a bootable Catalina installer USB, which can be used to install macOS on other computers. However, it is not easy to find the direct download link because Apple wants you to upgrade from Mac App Store. Fortunately, there are a few good websites that host the direct download link of macOS Catalina DMG. After that, you can burn the macOS dmg to USB to make it bootable for installation.

macOS Catalina 10.15 DMG Download Link 1: https://themacgo.com/macdownload/ (Wait a few seconds and the download starts automatically.)

macOS Catalina 10.15 DMG Download Link 2: https://drive.google.com/drive/folders/1ELQXMuuVWddamLPG0RHjyvaNW4r628CM (Password: Geekrar.com)

macOS Catalina 10.15 DMG Download Link 3: http://www.mediafire.com/file/wazr84baudhi27h/macOS_Catalina_DMG_by_Geekrar.rar/file

macOS Catalina 10.15 DMG Download Link 4: https://sundryfiles.com/G54 (Premium account required for download!)

macOS Catalina 10.15 InstallESDDmg PKG Download Link : http://swcdn.apple.com/content/downloads/61/56/041-83630-A_8RCIBB415Y/7jqh3nh97ood2mjej7hdgpx7fgh5c3fi9g/InstallESDDmg.pkg

macOS Catalina 10.15 VMware Image Download Link: https://www.mediafire.com/file/yrd1py7od5911zt/Catalina_Virtual_Disk_Image_by_Techsviewer.rar/file

Mac os catalina bootable usb on windows

macOS Catalina 10.15 VirtualBox Image Download Link: https://www.mediafire.com/file/yrd1py7od5911zt/Catalina_Virtual_Disk_Image_by_Techsviewer.rar/file

Tips: After downloading macOS Catalina .dmg file, it is time to make a macOS bootable USB from it. For this purpose, you can give a try on UUByte DMG Editor, one of the most popular software to create a Catalina USB installer on both Windows PC and Mac.

Part 2. Download macOS Catalina From Mac App Store

Apple always recommends its users downloading macOS install file from Mac App Store for security reasons. It is safe and easy. But the actual downloaded file is not an dmg file. Instead, it is an app called Install macOS Catalina, which is used to make the upgrade from current macOS to Catalina. For a clean install, it is better to download the dmg file and make an installer USB.

Note: Make sure to back up your Mac prior to installing macOS Catalina.

Step 1: Go to Mac App Store and search macOS Catalina. Then hit on 'Get' to download page.

Step 2: Doing this will open System Preferences followed by the section of Software Update, where you will find MacOS Catalina ready to download. Hit the option saying 'Upgrade Now' and download MacOS Catalina on your Mac.

Step 3: Next, macOS Catalina upgrade will ask for system reboot. Complete the process and install macOS Catalina on that computer.

Downloading macOS Catalina Install app works fine on my of newly devices but it could be problems for old Macs even it is officially supported by Catalina. If this is the case, then you have to patch the OS and install Catalina again. However, you need find a third-party app to do the dirty work. We will talk about this in Part 3.

Part 3. Download macOS Catalina 10.15 Installer with macOS Catalina Patcher

Although it may appear easy to try out the conventional approach of downloading macOS update in Software Update, there are a few known issues on old Macs shipped in 2013 or earlier, meaning the download progress can not be completed successfully. That's why macOS Catalina Patcher tool comes into help. This patching tool makes the job even simpler for installing macOS Catalina on unsupported Mac models.

However, the file size of these updates differs depending on the Mac device you are using. That means the downloaded update might not necessarily be the full installer version. For instance, if you wish to keep the installer file as archive for further application, or use it to generate bootable flash drive, this file size won't be sufficient.

Usb Bootable Mac Os Catalina

Fortunately, with macOS Catalina Patcher tool, you can simply download the entire update of macOS setup from Apple's servers. Let's check out the stepwise instructions of how to use this software tool to download the macOS Catalina DMG.

Step 1: Download a copy of macOS Catalina Patcher from this link.

Step 2: After downloading and attempting to install, an error notification will be prompted. It is due to the unavailability of developer verification credential for macOS. Now, go to System Preferences -> Security & Privacy. Then find the button saying 'Open Anyway' to let the app run.

Apple os catalina usb bootable

Step 3: Open macOS Catalina Patcher app and from the main menu, navigate to Options to uncheck the box saying 'Auto-apply Post Install Patches'. As you are done with the previous step and move to the screen as in the link below, hit Download a Copy.

Step 4: The following screen will notify the file size of macOS Catalina you are to download. The resolution is around 7GB and after the download, it will automatically get stored in the Downloads folder. Then hit Continue to initiate the process of download.

Step 5: The download time of the file will depend upon the internet connection and its speed. So, you might have to wait for some while for the process to complete. Eventually, the entire macOS Catalina setup file will be available on your device.

Closing Words

Well, that is all for the day. Hopefully, the above methods were helpful in guiding you on how to download macOS Catalina for both supported and unsupported Macs. When the download is finished, the next step is to burn the DMG file to USB. Then boot macOS from USB and starts the installation wizard.

It does not matter whether you use macOS or Windows 10. It’s just a matter of time until your device will refuse to start, which could happen for many reasons, including (and not limited to) file corruption, hardware failure, and buggy update. If the unexpected happens with an Apple computer, you can use a macOS bootable USB with the installation media to repair it.

This is one of the main reasons you should consider making a macOS bootable USB when your device is working properly. However, if none of your devices (MacBook, MacBook Air, MacBook Pro, iMac, Mac Pro, or Mac Mini) aren’t working when you need them the most, then you can use a PC to rescue your Apple device. You can use a Windows 10, Windows 8.1, or Windows 7 device to quickly create a USB bootable installation media to reinstall macOS Catalina or Big Sur on your Mac.

In this guide, you’ll learn the steps to create a macOS Catalina bootable USB installation on Windows 10, which you can use to reinstall or upgrade the Apple OS.

Requirements

Before proceeding, you’ll need the following:

Bootable Usb Drive Macos Catalina

  • Broken Mac computer running macOS (version 10.12, 11, or later).
  • A trial copy of the TransMac software.
  • One high-quality USB flash drive with 16GB of storage.
  • Copy of macOS (DMG file).

Create macOS bootable USB installation media

To create a bootable USB drive with macOS, use these steps:

  1. Download and install TransMac on the Windows 10 device.

    Quick note: This is a paid software, but it gives you a 15-day trial, which is more than enough time. (If this works for you and you want to support the developer, you can purchase the full version.)
  2. Connect the USB flash drive. (If you have any data on the flash drive, remember to make a backup, as everything on it will be erased.)

  3. Right-click the TransMac app and select the Run as administrator option.

  4. Click the Run button. (If you’re using the trial version, wait 15 seconds.)

  5. Right-click the USB flash drive, select the Format Disk for Mac option from the left navigation pane.

    Quick note: You want to do this before creating the bootable media because there is a good chance that the drive was formatted using a Windows device. If this is the case, the chances are that it’s using an MBR partition, and the USB drive needs a GPT partition to work on a Mac.
  6. Click the Yes button to format the drive on the warning message.

  7. Confirm a name for the drive. For example, “macOS bootable USB.”

  8. Click the OK button.

  9. Click the Yes button.

  10. Click the OK button.

  11. Right-click the USB flash drive and select the Restore with Disk Image option from the left navigation pane.

  12. Click the Yes button to confirm the erase of the USB flash drive data.

  13. Click the browse button on the right.

  14. Select the .dmg file with the macOS installation files.

  15. Click the Open button.

  16. Click the OK button.

  17. Click the Yes button.

Once you complete the steps, you can now insert the USB flash drive on your Mac computer to install, reinstall, or upgrade the operating system to the latest macOS version, which can be Sierra, Catalina, Big Sur, or higher.

Create Mac Os Catalina Bootable Usb

Create a GPT partition on USB flash drive

If the USB flash drive is not working with TransMac, it could still be a partition problem. In this case, you may need to redo the entire process again. However, this time you should use the following steps to use the Diskpart command-line utility on Windows 10 to create the appropriate GPT partition, and then follow the above instructions.

How To Create A Bootable Usb For Macos Catalina

To create a GPT partition on a removable drive, use these steps:

How To Create A Usb Installer For Macos Catalina

  1. Open Start.

  2. Search for Command Prompt, right-click the top result, and select the Run as an administrator option.

  3. Type the diskpart command and press Enter.

  4. Enter the list disk command to view all drives connected to your computer and press Enter.

  5. Type the select disk command followed the number assigned for the USB flash drive (for example, select disk 4), and press Enter.

  6. Enter the clean command and press Enter.

  7. Type the convert GPT command and press Enter.

  8. Enter the create partition primary command and press Enter to complete the process.

How To Create A Catalina Install Usb

Once you formatted the USB flash drive with a GPT partition, you can use the instructions mentioned above to use TransMac to create a bootable media, but this time skip steps No. 5 through 10 and continue on step 11.

Create Macos Catalina Install Usb On Windows 10

After the process completes, which can take up to an hour, connect the USB flash drive and power on your Mac holding down the Option key, select the USB drive to begin installing macOS.

How To Make A Bootable Usb For Macos Catalina

If you have problems creating the bootable media, you can get a USB flash drive that comes with macOS Sierra, El Capitan, Catalina, etc., on it with the link mentioned below. (I haven’t tried it personally, but it’s worth the try if nothing works.)