Error "macOS Catalina.app does not appear to be a valid OS installer application." It appears the Catalina Install file downloaded from Apple is only a stub as it is only 19.1MB. How do I download the full install?

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Error "macOS Catalina.app does not appear to be a valid OS installer application." It appears the Catalina Install file downloaded from Apple is only a stub as it is only 19.1MB. How do I download the full install?

When I issue the createinstallmedia command per instructions in https://support.apple.com/en-us/HT201372, I am getting error "macOS Catalina.app does not appear to be a valid OS installer application." It appears the Catalina Install file downloaded from App Store is only a stub as it is only 19.1MB. How do I download the full install?

MacBook Pro 13″, OS X 10.11

Posted on Nov 16, 2020 11:11 AM

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Answer 1

jimtunes Author

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Nov 16, 2020 5:37 PM in response to PRP_53

I guess I'm not being clear. I follow this link: https://itunes.apple.com/us/app/macos-catalina/id1466841314?ls=1&mt=12 which opens the Apple Apps Store (see image). I have clicked on Download button by both left clicking and by holding command key and left clicking, and then the download starts and works the same in either case. It takes 10-15 seconds, and the resulting file "Install MacOS Catalina.app" in Applications directory is 19.1MB, and automatically starts the Catalina Install window I included in my last post. I have no opportunity to create the USB install disk. If I cancel the install, and issue the command from Apple.com listed in my first post, I receive the error in question.

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Answer 2

Nov 18, 2020 3:08 AM in response to PRP_53

OK, found it - try this URL (published in Oct 2019) which has links to the FULL installers for OSs Catalina 10.15 to Yosemite 10.10: https://tidbits.com/2019/10/28/redownload-archived-macos-installers-to-address-expired-certificates/

Scroll down to the heading "Getting New Installers", the links are under here.

If you read the text below the heading, it states the installers expiry dates are set to April 2029!

The links will take you to App Store again, but will download the full app. I know, I just tried downloading Catalina, and it said it was 9GB in size (roughly).

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Answer 3

PRP_53

Level 10

91,369 points

Nov 17, 2020 2:42 AM in response to jimtunes

Then Apple has changed things around. I was successful in downloading the Full Catalina Installer on November 2, 2020 and made the USB Installer. Guess they changed things around after the release of Big Sur?

That said have a look over Here. There seems to be a way outside of the Apple Apps Store. The link is external but safe. Read it carefully before attempting to process. I assume not responsibility for the outcome.

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Answer 4

Nov 16, 2020 11:40 AM in response to jimtunes

It does that after a certain length of time (especially Mojave and Catalina), it has a expiry date for the installer you downloaded earlier. I think it's shelf life is about 5-6 months.

Try here instead - it should be the full fat download: https://support.apple.com/en-gb/HT211683

Then scroll down to 'Download macOS' section.

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Answer 5

jimtunes Author

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Nov 16, 2020 4:36 PM in response to PRP_53

After deleting the previous download, I tried again while holding command key and it didn't appear to do anything different. It downloads in less than 15 seconds and is 19.1MB again. It appears Apple has decided to have the primary download occur during the installation process which invalidates the ability to build a bootable installation disk per their own instructions. Does anyone know if they have an ftp site (or other method) where the full install can be downloaded? The App Store appears a dead end. Is there a way to interrupt the installer after the download is complete but before the actual install?

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Answer 6

jimtunes Author

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9 points

Nov 16, 2020 12:45 PM in response to Michael Hutchison

Unfortunately this is the same process I did before with the same resulting error. The install link on the page you sent me to, sends me to the App Store and it only downloads a small stub. It appears the install process initiates the download. Since I'm doing a clean install, I want to build a USB install that I can boot to and install from there so need the full install on my system to build the bootable USB drive.

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Answer 7

Nov 18, 2020 2:45 AM in response to PRP_53

That's surprising, that it no longer works, I downloaded the Mojave installer a month or so back, because the previous installer had expired. So I assumed it would be OK for Catalina as well. Sorry about that.

Apple are at it again, messing up stuff that previously worked!! So annoying.

In the meantime, I'll have a look around, and see if I can find a full working installer.

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Answer 8

PRP_53

Level 10

91,369 points

Nov 16, 2020 1:23 PM in response to jimtunes

Try this once you are the Apple Apps Store Catalina. Hold Command and click download. You will know almost immediately if you are getting the Stub or the Full Installer

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