macOS Cacher for Mojave and Earlier

What the macOS installer caching Worklet does

This Automox Worklet™ downloads macOS Big Sur installers from Apple's software update servers and caches them locally on your endpoints. The Worklet is designed specifically for macOS Mojave and earlier, which lack the built-in caching mechanism available in Catalina and newer versions.

The Worklet performs validation checks before and after download, verifying installer integrity using SHA checksums. It manages the download process with resume capability and stores the installer in a temporary directory before moving it to the Applications folder.

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This caching approach eliminates the need to download 12-13GB of installer data across your network during each upgrade deployment, significantly reducing bandwidth usage and deployment time.

Why cache macOS installers on pre-Catalina endpoints

Upgrading macOS on older versions requires the installer to be available locally. Unlike Catalina and newer systems, Mojave and earlier versions do not automatically cache update files, forcing each endpoint to download the full installer package during upgrades.

Deploying installers before upgrades allows you to stage updates efficiently. Your endpoints can complete upgrades faster when the installer is already present, reducing deployment windows and network congestion during critical update periods.

How macOS installer caching works

1. Evaluation phase: Checks whether the endpoint is running macOS Mojave or earlier, verifies available disk space exceeds 40GB, and confirms whether the Big Sur installer already exists in the Applications folder.

2. Remediation phase: Downloads the macOS Big Sur InstallAssistant package from Apple's servers using curl with resume capability, validates the package SHA checksum, installs the package to the system, verifies the installer DMG file integrity, and cleans up temporary download files.

macOS installer caching requirements

• Endpoints running macOS Mojave, High Sierra, or earlier versions

• Minimum 40GB of available disk space for the installer download and extraction

• Network connectivity to Apple's software update servers (swcdn.apple.com)

• Administrative privileges to write to the /Applications directory and system installer paths

Expected macOS installer state after caching

After the Worklet completes successfully, the macOS Big Sur installer appears as a complete application in your Applications folder at /Applications/Install macOS Big Sur.app. The installer package contains the full SharedSupport DMG file required for in-place upgrades.

You can verify successful caching by checking whether the installer application is present and by confirming the installer's integrity using the SHA checksums embedded in the Worklet. With the installer cached locally, you can proceed with Big Sur upgrades without requiring each endpoint to download the 12-13GB package again.

How to validate macos cacher for mojave and earlier changes

1. Run this Worklet on a pilot macOS endpoint and review evaluation output for macos cacher for mojave and earlier.

2. Confirm Automox activity logs show successful completion and exit code 0.

3. Verify endpoint state using checks aligned to evaluation script logic, such as exit, else.

4. Validate remediation effects from script operations such as function, exit, else, then rerun evaluation for compliance.

For technical validation, compare endpoint state to the Worklet evaluation logic and remediation flow for macos cacher for mojave and earlier. This supports repeatable security workflows, faster change control review, and auditable compliance evidence.

Useful script references for this Worklet include evaluation operations such as exit, else and remediation operations such as function, exit, else. Use these indicators to verify that endpoint changes match intended policy outcomes.