macOS High Sierra, also known as version 10.13, represents a pivotal moment in the evolution of Apple’s desktop operating system. Officially released on September 25, 2017, this version followed the nomenclature established by previous "refinement" releases such as Snow Leopard, Mountain Lion, and El Capitan. Its primary objective was not to introduce a radical visual redesign, but to overhaul the underlying technologies that govern data storage, graphics processing, and video efficiency.

While modern users might view High Sierra as a legacy operating system, its architectural changes laid the foundation for the high-performance macOS ecosystem we interact with today. By shifting the default file system and embracing advanced media codecs, Apple ensured that older hardware could remain relevant for years while preparing the platform for the demands of 4K video and virtual reality.

The Technological Pillars of macOS High Sierra

The significance of macOS High Sierra lies in its "under-the-hood" improvements. These technical shifts were mandatory transitions to accommodate the move from traditional spinning hard drives to high-speed solid-state drives (SSDs).

The Introduction of Apple File System (APFS)

Perhaps the most consequential change in High Sierra was the replacement of the aging HFS+ file system with the Apple File System (APFS). Developed specifically for flash and SSD storage, APFS introduced several features that optimized performance and data integrity.

APFS utilizes 64-bit architecture, which is a massive leap from the 32-bit limitations of HFS+. This transition allowed the system to manage storage with greater precision and speed. One of the most noticeable improvements for users was the "instant cloning" of files and directories. Instead of copying data bit by bit, APFS creates a new reference to the same data on the disk, making the process nearly instantaneous while saving space.

Furthermore, APFS introduced native encryption as a primary feature, improving security at the file system level. It also incorporated "snapshots," which are point-in-time, read-only instances of the file system. These snapshots make backups via Time Machine significantly more efficient and allow for easier system recovery in the event of software failure.

Metal 2 and the Leap into Virtual Reality

With High Sierra, Apple introduced Metal 2, an update to its low-level graphics API. Metal 2 was designed to give developers even more direct access to the Graphics Processing Unit (GPU), reducing overhead and boosting frame rates in games and creative applications.

Crucially, Metal 2 brought support for External Graphics Processors (eGPUs) over Thunderbolt 3. This allowed users with slim laptops, like the MacBook Pro, to connect desktop-class graphics cards for intensive tasks such as 3D rendering or high-end gaming. High Sierra also marked the first time macOS officially supported Virtual Reality (VR) content creation, specifically optimized for the HTC Vive and applications like Final Cut Pro X and SteamVR.

High Efficiency Video Coding (HEVC)

As 4K video became the industry standard, the older H.264 codec struggled with large file sizes and high bandwidth requirements. High Sierra introduced support for HEVC (High Efficiency Video Coding), also known as H.265.

HEVC allows for video compression that is up to 40% more efficient than H.264 without sacrificing image quality. This change was essential for the ecosystem, as it enabled Macs to stream high-quality 4K video more smoothly and stored more footage in less disk space. Hardware acceleration for HEVC was specifically optimized for Macs with 6th-generation Intel Core processors (Skylake) and newer, ensuring that the CPU wouldn't be overwhelmed during playback or encoding.

Key Feature Refinements and App Updates

Beyond the invisible technical upgrades, macOS High Sierra brought meaningful enhancements to the core applications that users interact with daily.

Safari 11: Privacy and Performance

Safari 11 introduced Intelligent Tracking Prevention (ITP). This feature utilized machine learning to identify and block the trackers used by advertisers to follow users across different websites. By limiting cross-site tracking, Safari strengthened user privacy significantly.

Another notable addition was the ability to disable autoplay videos. Users could customize settings on a per-site basis, ensuring that intrusive media would not play automatically when a page loaded. Additionally, "Reader Mode" could be set to activate automatically for compatible articles, providing a distraction-free reading experience.

Photos: Professional-Grade Editing Tools

The Photos app in High Sierra underwent a substantial transformation. It received a persistent sidebar for easier navigation and a redesigned "Edit" view. Apple integrated professional-grade tools like "Curves" for fine-tuning color and contrast, and "Selective Color" for making specific adjustments to individual hues.

The app also improved its organization capabilities. The "People" album became more accurate thanks to advanced facial recognition, and these tags began syncing across devices via iCloud Photo Library. Support for third-party project extensions allowed users to order prints or create photo books directly through services like Shutterfly without leaving the app.

Notes and Mail Improvements

The Notes app became more functional for organization by adding the ability to pin important notes to the top of the list and insert tables for structured data. In the Mail app, Apple optimized storage, claiming that the mail database would occupy up to 35% less space than in previous versions. The search functionality within Mail was also enhanced with "Top Hits," which uses relevance algorithms to surface the most pertinent emails based on recent interactions.

Hardware Compatibility and Requirements

High Sierra was known for its broad compatibility, supporting many Macs that were originally released in the late 2000s. However, specific features required more modern internal hardware.

Supported Mac Models

To install macOS High Sierra, a device generally needed to be one of the following:

  • MacBook: Late 2009 or newer
  • MacBook Air: Late 2010 or newer
  • MacBook Pro: Mid 2010 or newer
  • Mac mini: Mid 2010 or newer
  • iMac: Late 2009 or newer
  • Mac Pro: Mid 2010 or newer
  • iMac Pro: 2017 models

Feature-Specific Requirements

While the OS could run on the models listed above, certain advanced features had stricter hardware demands:

  • APFS: Required a Mac with all-flash internal storage (SSD) for automatic conversion, though it could be manually enabled on some Fusion Drives.
  • HEVC Hardware Acceleration: Required 6th-generation Intel processors or newer (e.g., Late 2015 27-inch iMac or 2016 MacBook Pro).
  • Metal 2 eGPU Support: Required a Mac with Thunderbolt 3 ports (Late 2016 MacBook Pro or 2017 iMac).
  • Handoff and AirDrop: Required Bluetooth 4.0/LE, typically found in 2012 or newer models.

Security Challenges and Current Status

Understanding the current state of macOS High Sierra is vital for anyone considering using it today. As of November 2020, Apple has officially ceased providing security updates for version 10.13.

Is macOS High Sierra still safe to use?

From a modern cybersecurity perspective, using macOS High Sierra as a primary operating system is risky. Because it no longer receives security patches, the system remains vulnerable to exploits discovered after 2020. This includes vulnerabilities in the Safari browser, which has not been updated to the latest standards on this OS version.

In its history, High Sierra also faced a critical security flaw known as the "Root Bug," where anyone could gain administrative access by typing "root" as a username with no password. While Apple patched this specific issue in update 10.13.1, other subsequent vulnerabilities remain unaddressed in the final build (10.13.6).

Software Compatibility Issues

Modern software developers have largely moved on from High Sierra. Most current versions of popular applications, such as the Adobe Creative Cloud suite, Microsoft 365, and even web browsers like Google Chrome, require at least macOS 11 (Big Sur) or newer. Users sticking with 10.13 will find themselves trapped using older, potentially buggy versions of their favorite tools.

Legacy Use Cases for macOS High Sierra

Despite the security risks, there are specific scenarios where High Sierra remains a viable choice:

  1. Older Hardware Maintenance: For Macs that cannot officially upgrade past 10.13, High Sierra is the most "modern" official OS available. It allows these machines to function as basic word processors, offline file servers, or dedicated media players.
  2. 32-Bit Application Support: High Sierra was one of the last versions to offer robust support for 32-bit applications. While macOS Mojave (10.14) also supports them, High Sierra is often preferred for specialized legacy software that might struggle with the transitions introduced in later versions.
  3. Educational and Testing Environments: It serves as a useful environment for developers who need to test how older software behaves on the APFS file system.

Summary of Key Specifications

Category Requirement / Detail
Version Number 10.13
Release Date September 25, 2017
Final Update 10.13.6 (July 2018)
Last Security Update November 2020
Minimum RAM 2 GB
Storage Space Required ~14.3 GB for upgrade
Default File System APFS (for SSDs)

Conclusion

macOS High Sierra was a transformative release that prioritized structural integrity over visual novelty. The introduction of APFS, Metal 2, and HEVC modernized the Mac experience, ensuring that the hardware could keep pace with the rapid advancement of flash storage and high-resolution media. However, in today’s landscape, High Sierra is an obsolete operating system. While it can breathe life into older machines for specific tasks, it lacks the security infrastructure required for safe browsing and modern professional workflows. For most users, upgrading to a supported version of macOS—or using tools like OpenCore Legacy Patcher to install newer versions on unsupported hardware—is the recommended path forward.

FAQ

Can I still download macOS High Sierra?

Yes, macOS High Sierra is still available through the Mac App Store via direct links provided on Apple’s support pages. However, it will not show up in general search results if your current Mac is running a significantly newer version of macOS.

Does macOS High Sierra support the new Apple M1 or M2 chips?

No. macOS High Sierra was designed exclusively for Intel-based Macs. The transition to Apple Silicon occurred with macOS Big Sur (version 11.0).

What should I do if my Mac is stuck on High Sierra?

If your hardware does not support newer versions of macOS, consider using the machine for offline tasks or light web browsing with a third-party browser that still offers limited legacy support. Alternatively, look into the "OpenCore Legacy Patcher" project, which allows many older Macs to run newer versions of macOS, though this requires technical expertise.

How do I check if my Mac is using APFS?

Go to the Apple Menu > About This Mac > System Report. Under the "Storage" or "SATA/SATA Express" section, you can see the "File System" listed for your primary drive. If it says APFS, the conversion was successful during the High Sierra installation.