Installation failed: An error occurred while installing the selected updates??

Try it from here:

Download macOS Mojave 10.14.6 Combo Update

Boot into Safe Mode and then install:

Use safe mode to isolate issues with your Mac - Apple Support

Same issue here. Also had this issue with the first 10.14.6 Supplemental Update (never resolved).

I have tried running Disk Utility/First Aid, including running it from the Recovery partition. No change in behavior.

I also cannot install from the downloaded version.

I also tried downloading the 10.14.6 Combo Updater from 9/26/2019 and got a similar failure message when trying to install that one.

I too have this same issue. I am unable to install any of the automatic updates that come.

I have tried (unsuccessful in all outcomes):

• Automatic updates of the packages for Mojave (Safari update worked but not the Security Updates)
• Manually downloading the packages and trying to install
• Deleting the apple.com.appstore folders and cache and trying again
• Booting to safe mode and manually installing from the above Download link

Still the same thing here. I even tried installing Catalina and that fails.

Then I tried this sequence:

Cloned my boot drive to an external SSD.

Boot from external.

Erase internal SSD.

Run Catalina Installer, targeting internal. - Fails

I was able to clone back to my internal, so I'm back where I was. I'm just not able to install or update my OS.

Now I'm wondering if there is an issue with one of the invisible partitions/containers that that OS uses? Just a theory.

I'm attaching the error log from my last attempt to install the Security Update 2019-001 for Mojave.

Hoping that provides someone some clues?

Yes. No success.

Great insight!

How would I be able to find this log to review and/or post it here?

I don't know if it's available from the System Preferences > Software Update area. You might need to download the stand-alone or combo update installers from the link that macjack posted above: Apple - Support - Downloads

Within the installer app, you should find in the Window > Installer Log, or do a cmd-L. Hope that helps!

Boot into Recovery Mode and run Disk Utility > First Aid on your Mac volume. After that try again.

About macOS Recovery - Apple Support

Have the tried downloading the updates you need from this site? It uses a different server.

Apple - Support - Downloads