How do I incrementally upgrade from macOS 14.2 to 15.5?

The upgrade appeared to load but would not complete and displayed a "try later" type of message. When this happened on a Windows machine I had, the approach was to load the updates one at a time. I have been using the Mac for a number of years but am not as knowledgable about the OS. Thank you.


Neither 15.5 nor 14.7 would complete installation


[Edited by Moderator]

iMac 21.5″, macOS 14.2

Posted on May 29, 2025 1:49 PM

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Jun 3, 2025 2:20 AM in response to Vinte61

As a starting point


What follows is based upon the computer is currently running Sonoma 14.2


Is that correct ?


If Yes


Terminal command below


softwareupdate --fetch-full-installer --full-installer-version 14.7.6


This should manually download the Full Version of Sonoma 14.7.6


Be aware the file would be about 12 to 14 GB in size


It will create a New Application in the applications folder called " Install Sonoma app "


It does Not Auto Launch


Make a Time Machine Backup Before proceeding


As my colleague @Matti Haveri has suggested


Restart the computer in  Safe Mode


Launch the application link another application and follow the prompts

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Jun 2, 2025 4:28 PM in response to Owl-53

Hello Owl-53 and thank you for the reply. It found a lot but I certainly am not the guy to decode it :o)


Software Update found the following full installers:

* Title: macOS Sequoia, Version: 15.5, Size: 15283299KiB, Build: 24F74, Deferred: NO

* Title: macOS Sequoia, Version: 15.4.1, Size: 15244333KiB, Build: 24E263, Deferred: NO

* Title: macOS Sequoia, Version: 15.4, Size: 15243957KiB, Build: 24E248, Deferred: NO

* Title: macOS Sequoia, Version: 15.3.2, Size: 14890483KiB, Build: 24D81, Deferred: NO

* Title: macOS Sequoia, Version: 15.3.1, Size: 14891477KiB, Build: 24D70, Deferred: NO

* Title: macOS Sonoma, Version: 14.7.6, Size: 13338327KiB, Build: 23H626, Deferred: NO

* Title: macOS Sonoma, Version: 14.7.5, Size: 13337289KiB, Build: 23H527, Deferred: NO

* Title: macOS Sonoma, Version: 14.7.4, Size: 13332546KiB, Build: 23H420, Deferred: NO

* Title: macOS Ventura, Version: 13.7.6, Size: 11910780KiB, Build: 22H625, Deferred: NO

* Title: macOS Ventura, Version: 13.7.5, Size: 11916960KiB, Build: 22H527, Deferred: NO

* Title: macOS Ventura, Version: 13.7.4, Size: 11915317KiB, Build: 22H420, Deferred: NO

* Title: macOS Monterey, Version: 12.7.4, Size: 12117810KiB, Build: 21H1123, Deferred: NO

* Title: macOS Big Sur, Version: 11.7.10, Size: 12125478KiB, Build: 20G1427, Deferred: NO

* Title: macOS Catalina, Version: 10.15.7, Size: 8055650KiB, Build: 19H15, Deferred: NO

* Title: macOS Catalina, Version: 10.15.7, Size: 8055522KiB, Build: 19H2, Deferred: NO

* Title: macOS Catalina, Version: 10.15.6, Size: 8055450KiB, Build: 19G2021, Deferred: NO

* Title: macOS Mojave, Version: 10.14.6, Size: 5896894KiB, Build: 18G103, Deferred: NO

* Title: macOS Mojave, Version: 10.14.4, Size: 5894794KiB, Build: 18E2034, Deferred: NO

Pauls-iMac-6:~


Thank you for the help!

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Jun 3, 2025 2:24 AM in response to Vinte61

Predicated on a successful Sonoma 14.7.6 installation 🤞


Keep using the computer in this state for a couple of days


All is good


Repeat the same procedure using this Terminal command


softwareupdate --fetch-full-installer --full-installer-version 15.5

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How do I incrementally upgrade from macOS 14.2 to 15.5?

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