Catalina Os Installer

Attempting to download macOS Catalina from the Mac App Store you may find that a small version of the “Install macOS Catalina.app” file downloads to the “Applications” folder, rather than the complete 8.1 GB installer file.

Attempting to download macOS Catalina from the Mac App Store you may find that a small version of the “Install macOS Catalina.app” file downloads to the “Applications” folder, rather than the complete 8.1 GB installer file.
The first hurdle is to actually get the macOS Catalina installer onto a Mac. This is an unavoidable part of the process and will require just over 8 gigabytes of drive capacity to store.
Install macOS 10.15 Catalina. After downloading macOS 10.15 Catalina, the installer will begin on its own and launch automatically. Follow the on-screen instructions to complete the upgrade and start using macOS Catalina. When prompted, select the internal hard drive to upgrade the Mac or an external hard drive to create an external macOS drive.
As with any regular OS update, Catalina should appear as an option to upgrade to, as it would if you were on a natively supported Catalina Mac. Hit “Upgrade Now” and it will begin to download the Catalina DMG Installer straight to your Applications folder.

The tiny (just tens of megabytes) incomplete installer requires an internet connection during usage to download the rest of the Catalina update files. Additionally, it does not allow to create a macOS Catalina USB installer drive for use on multiple computers.

How to Perform a Clean Install of macOS Catalina. Download macOS Catalina from the Mac App Store Direct Link. Once the download is complete, close the installer window by selecting the Quit.

In this tutorial, I’ll show you how to download the complete “Install macOS Catalina.app” file from Apple server using the “macOS Catalina Patcher” app instead of via the Mac App Store.

A similar mini-installer issue occurred previously with some users getting a tiny incomplete macOS High Sierra installer and macOS Mojave installer too and I covered a similar workaround here and here to download the complete installer file from Apple server.

About the app

In this workaround, we’re going to use the macOS Catalina Patcher app from the dosdude1.com. This app is intended for those with unsupported Macs and Hackintosh users, but any Mac user can use the app to be able to download the complete macOS Catalina installer file from Apple server. For our purposes in this particular walkthrough, we will use the app only to download the complete installer file.

Note! This method relies on a third party app from an unverified third party source. If you are not comfortable with using unvetted and unverified software, do not follow this process.

Let’s begin

Downloading the complete “Install macOS Catalina.app” file from Apple server using the “macOS Catalina Patcher” app is a really easy process. Now, step by step guide.

Go to the official website of the “macOS Catalina Patcher” app here and download the app.

The download link is labeled as “Download Latest Version” on that page.

Launch the “macOS Catalina Patcher” app.

Note! By default, macOS preventing apps from unidentified developers or sources from being launched. So you most likely will get an alert message that says: “macOS Catalina Patcher.app can’t be opened because it is from an unidentified developer”. To allow just one specific app to run do the following:

Hold down the Control key and click the app icon. From the contextual menu choose Open.
A popup will appear asking you to confirm this action. Click the Open button.

Click the “Continue” button, and then select “Download a Copy”.

Confirm that you want to download the “Install macOS Catalina.app” app to start the download to your hard drive.

Close the “macOS Catalina Patcher” app when the download is complete and locate the “Install macOS Catalina.app” file you downloaded.

Note! The download will be completed when you are prompted to choose an installation method. See the screenshot below.

Conclusion

That’s it, you’re done. Now you have the complete “Install macOS Catalina.app” file downloaded. So simple isn’t it?

You can confirm that you have the complete “Install macOS Catalina.app” file by getting info on the file. For this simply select the file and click the Spacebar key (or right-click on the file and choose “Get Info”). The complete installer should be around 8.1 GB rather than the tiny (just tens of megabytes) incomplete installer that requires additional downloads.

Note! Remember, the “Install macOS Catalina.app” file deletes itself automatically after macOS Catalina has successfully installed. Therefore, you may want to make a backup by having previously copied it to external storage.

Let me know in the comments section if you know another way to download the complete “Install macOS Catalina.app” file rather than the tiny incomplete installer.

I hope this article has helped you learn how to downloaded the complete “Install macOS Catalina.app” file from Apple server. If this article has helped you then please leave a comment

Thanks for reading!

Arthur is a designer and full stack software engineer. He is the founder of Space X-Chimp and the blog My Cyber Universe. His personal website can be found at arthurgareginyan.com.

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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.

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:

Plug the USB flash drive into your Mac.
Launch the “Disk Utility” application.
On the left-hand pane, select the USB drive (not the partition under it, if any).
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.
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).
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.

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:

Insert the USB flash drive.
While holding the “option” key down, turn on the Mac to display the Startup Manager.
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.
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.

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:

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.
The macOS Recovery screen contains a top-level “macOS Utilities” menu.
Click on the “Utilities” menu and select “Startup Security Utility”. Input your administrator password when prompted.
In the Startup Security Utility, under “Allowed Boot Media”, select the “Allow booting from external or removable media” option.
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.)
Quit the macOS Utilities to restart the Mac.
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:

Select the “Disk Utility” option and click the “Continue” button on the bottom to launch the “Disk Utility” application.
On the left-hand pane, select the internal hard drive (not the partition under it, if any).
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.
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.

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

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

Mac Os Catalina Installer App Download

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.