There is no macOS Catalina 10.15 available, Apple removes all previous full installers from the App Store
If you’ve owned a Mac for a while, you’re well-aware of the fact that updating macOS to the latest version is a pretty straightforward procedure.However, if you’re looking to create a bootable USB drive, a full installer file is necessary, and the update you download from Apple’s servers might not always be the full installer, particularly with Catalina and Mojave (Big Sur does not.
when a revised version is released.
The package you downloaded is not the upgrade installer app but an update for Catalina, you need
to be running a previous version of Catalina before that will install. Put it in the Trash, empty the Trash.
You need to download the full installer app from the link below,
Open Safari and click on the blue text,
Go to Check Compatibility to see if your mac qualifies for macOS Catalina.
If it does go to the Download OS section and click on macOS Catalina 10.15.
This will redirect you to the App Store Catalina download page it should say
Get or Download.
This will download the Install macOS Catalina.app directly to your Applications folder.
It is about 12.24GBs in size so will take a while, be patient.
Double-click on the installer app to install Catalina this will install a full working version
of Catalina and the version will be the latest/ last ver 10.15.7.
Before upgrading make a full back up of your Mac.
Check that third party apps you use have updates available for the new OS.
Check that your printers/ scanners etc have updated drivers and software available for the new OS.
Connect your mac to your router via cable rather than rely on WiFi.
Do not use your mac while it is downloading
and do not use any other devices that share the same internet connection.
If the App Store says ‘Open’ then it is detecting a previous download of the install app
go to the Applications folder locate Install macOS Catalina.app.
Move it to the Trash, empty the Trash.
Restart, click on the link again, the App Store should say ‘Get' or 'Download'.
As you are considering upgrading to Catalina be warned it does not support 32bit apps.
Your Mac is probably running 32bit apps and these will need to be updated to 64bit apps,
some updates may be free, some may be paid. Use this app to discover which apps you have
are 32bit, https://www.stclairsoft.com/Go64/ then contact the developers of the software to see
if they are providing 64bit updates or alternatives.
Jul 29, 2021 10:44 AM