Why did I end up with duplicated apps when I upgraded macOS from Catalina to Big Sur?

Question

Why did I end up with duplicated apps when I upgraded macOS from Catalina to Big Sur?

When I updated my iMac (27in,2020) from Catalina (10.15.7) to Big Sur (11.7.10), I ended up with (mostly) duplicated apps in Applications folders under both the System directory and the Users -> username directory!

Can I just delete the duplicates, presumably from the username/Applications folder?

Plus...

To be safe, I downloaded a full installer for Catalina and created a bootable flash installer drive for it, but now I can't delete that installer app because it's "in use" (see attached)!

Since I'd done the same thing with Monterey, Ventura, and Sonoma (for future upgrades) and had no issues deleting those installer apps once I created bootable drives for each of them, I don't understand what was different (other than there seemed to be some confusion over the full installer file size, see attached excerpt).

Thanks in advance for any helpful advice!

iMac, OS X 10.11

Posted on Jan 22, 2025 1:41 PM

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Answer 1

a brody

Level 10

84,467 points

Jan 24, 2025 3:48 PM in response to BigMac-BigSur

You need a minimum of 50 GB free. Larger if your hard drive greater than 256 GB.

If safe mode doesn't let you delete those pending installation programs, you can use Target Disk Mode on your Mac, and connect it to another Mac. Many usergroups have people who have Macs that can help you out.

The software update fetch full installer only downloads the selected installer. The list is what's available on Apple's server. You can't use the Catalina installer on Big Sur. Only internet restore or a clone externally booted will let you downgrade as described on this tip:

How do I downgrade my Mac OS X operating … - Apple Community

Installers will stick around in the Applications folder if they aren't used. You may need to boot off an external hard disk and delete from the Application folder on your other volume the installers you don't need.

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Answer 2

Jan 24, 2025 12:49 PM in response to a brody

I appreciated the advice, and in fact had already tried it in Safe Mode, but I think the real issue is that this "InstallmacOSCatalina.app" is only 7.74GB while the original download was 8.26GB so something changed or got interrupted/corrupted.

The original fetch of the full installer had only single Catalina option, i.e. a single version 10.15.7, while (as you can see from my previous attachment), the next time I checked a few days later there were two 10.15.7 versions as well as two 10.15.6 versions!

In any case, I tried the Safe Mode option again and ended up with a little more clarity on the problem when I tried to open the app:

While back in normal startup, I still get the "in use" error message:

Should I just reinstall my current Big Sur 11.7.10, or maybe hope that making the jump to Monterey 12.x.x clears this up?

Thanks again for any advice!

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Answer 3

a brody

Level 10

84,467 points

Jan 22, 2025 2:41 PM in response to BigMac-BigSur

Restart the Mac in safe mode (shift key) with the external bootable installer removed immediately after shutting down the Mac. This will force it to recognize you can then delete the excess file.

The file will be situated in the applications folder.

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