Installing macOS software is a straightforward process, but for those curious about the intricate workings of installations, detailed logs are available for review. Here’s how to access them.
The installation files used in macOS are referred to as Packages and typically end with a .pkg extension. When you initiate a .pkg file on your Mac, Apple’s installer application conducts several complex operations to validate and set up the software.
Generally, .pkg files comprise a sequence of standardized procedures: first verification occurs, followed by decompression and transfer of payloads to the designated drive.
post-install scripts execute various tasks including installation verification, adjustment of file permissions, and performing any additional cleanup required. While this process seems seamless from the user interface perspective, much is happening behind the scenes.
Fortunately for users wanting insight into these processes, there exists an extensive log that documents everything occurring during installation. Accessing this log is simple; it can also be saved or printed if needed.
Understanding Package Installation Mechanics
Typically speaking, most .pkg files do not include an installer application themselves; rather they are processed by macOS’s Installer.app found on your Startup Disk at /System/Library/Core Services. The current version accompanying macOS Sequoia 15.3 is 6.2.
Upon double-clicking a .pkg file in Finder, macOS automatically launches the installer app and feeds it the necessary file path so that it may be opened successfully. To compile a list of all .pkg files residing on your Mac: press Command-F on your keyboard; adjust search terms to “Kind is Other,” then input “Installer” in the adjacent search box.
It’s worth mentioning that .pkg files act as Bundles—unique folders within macOS similar to most applications—and they can also house other packages within them.
This structure applies even for custom installers designed by developers which do not rely on Installer.app for execution.
The Evolution of Packaging: Flat Packages
With Mac OS X 10.5 Leopard’s introduction came Apple’s provision for developers to create flat installer package formats—single encoded entities maintaining the .pkg extension but bypassing bundle folder status while still being executed by Installer.app.
Flat-file packages restrict users from peeking inside using Finder’s Show Package Contents feature or Terminal commands ensuring configuration security when opened; however when activated through Installer.app—the contents execute without exposing internal data details.
Exploring Installation Logs Post Process
The standard display upon completing an install via Installer.app shows provided progress messages…
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