You remember the jokes, right? When Apple announced the macOS 10.13 High Sierra update back at WWDC 2017, the room laughed because it sounded like they just got high and stayed in the mountains. Craig Federighi even joked about the name being "fully baked."
But honestly? It was the most important "boring" update Apple ever shipped.
Most people want flashy new features—emojis, translucent windows, or some AI trickery. High Sierra didn't give you much of that. Instead, it ripped out the literal floorboards of the operating system and replaced them with steel. We’re talking about the transition from the ancient HFS+ file system to APFS. If that sounds like nerd-speak, just know it’s the reason your Mac didn't feel like a dinosaur three years later.
The APFS Revolution (and why your data survived)
For decades, Macs ran on HFS+. It was a relic from the floppy disk era. It was slow, prone to corruption, and it couldn't handle the way modern SSDs actually work. When the macOS 10.13 High Sierra update landed, it force-migrated millions of users to the Apple File System (APFS).
This was a massive gamble. Changing a file system is like trying to swap the engine of a car while it's doing 80 mph on the freeway. But it worked. APFS introduced "64-bit inode numbers," which basically means the computer can keep track of way more files with way more precision.
The coolest part? Atomic safe-save. Ever had your Mac crash while saving a document, only to find the file corrupted and gone forever? APFS fixed that. It writes the new data to a new location before unlinking the old data. If the power cuts mid-save, you just keep the old version. It's simple, but it saved countless hours of lost work for creatives.
Also, copying files became instant. Since APFS uses "cloning," it doesn't actually move the data bits when you duplicate a file on the same drive. It just creates a second pointer to the same data. You could duplicate a 10GB video file in half a second. It felt like magic.
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Metal 2 and the GPU struggle
Back in 2017, Apple was still trying to convince pro users that they cared about graphics. High Sierra introduced Metal 2.
It wasn't just about making games look slightly better. It was about offloading tasks from the CPU to the GPU. This update was the foundation for things we take for granted now, like smooth window animations and fast video rendering in Final Cut Pro. It also officially brought support for External GPUs (eGPUs).
Suddenly, a thin MacBook Pro could theoretically have the power of a desktop workstation if you plugged in a massive enclosure via Thunderbolt 3. Was it buggy at launch? Yeah, kinda. But it paved the way for the hardware-software synergy we see in the M-series chips today.
The Safari "War" on Annoyances
One of the best things about the macOS 10.13 High Sierra update was Safari 11. It was arguably the peak of the browser before it got cluttered.
Apple introduced Intelligent Tracking Prevention (ITP). Advertisers hated it. They literally wrote open letters complaining about it. ITP used on-device machine learning to identify and scrap the cookies that followed you from site to site.
And let's not forget the "Autoplay Blocking." High Sierra was the first time Safari would just... stop videos from screaming at you when you opened a news article. You could set per-site preferences. If you wanted one site to always be zoomed in at 120% and another to never play video, you could do that. It was a level of control that felt genuinely pro-user.
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HEVC: The reason your hard drive isn't full
Before High Sierra, we were all stuck with H.264. It was fine, but 4K video was starting to become the standard, and those files were huge.
High Sierra brought High Efficiency Video Coding (HEVC), or H.265. Basically, it offered up to 40% better compression than the old standard without losing quality. If you were an early iPhone user shooting 4K, this update was the only reason your Mac didn't run out of space in a week. It also added support for HEIF (High Efficiency Image File Format), which is why your photos are .heic files now instead of .jpg.
The "Root" Security Disaster
We can't talk about High Sierra without talking about the "Root" bug. It was embarrassing.
In late 2017, developer Lemi Orhan Ergin discovered that anyone could log into a High Sierra Mac by typing the username "root," leaving the password blank, and hitting enter a few times. It was a catastrophic security lapse. Apple scrambled. They pushed a patch within 24 hours, but for a day or two, the most secure OS in the world had its front door wide open.
It’s a reminder that even when Apple focuses on "refinement," things can break in spectacular ways.
Hardware Compatibility: The end of the road for some
High Sierra was a bit of a gatekeeper. It supported:
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- MacBook (Late 2009 or newer)
- MacBook Pro (Mid 2010 or newer)
- iMac (Late 2009 or newer)
- Mac mini (Mid 2010 or newer)
- Mac Pro (Mid 2010 or newer)
If you had a machine from 2008, you were stuck on Sierra. This was the era where Apple started tightening the requirements to ensure the SSD-optimized APFS would actually run well. If you tried to run High Sierra on an old spinning hard drive, the performance was... well, it wasn't great. APFS was built for flash, and it showed.
Why does 10.13 still matter?
You might think an OS from years ago is irrelevant. But High Sierra is often the "final" OS for many classic Macs.
If you find a cheap 2010 Mac Pro or a 2011 MacBook Pro, High Sierra is usually the last stop for official software. It's the bridge between the old world of physical discs and the new world of cloud-integrated, mobile-first computing. It’s a stable, fast, and relatively lightweight OS.
Interestingly, many people in the "vintage" Mac community still use High Sierra because it’s the last version of macOS that supports many older 32-bit apps without the massive headaches introduced by Catalina (10.15). If you have old Adobe software or legacy music plugins, High Sierra is your safe haven.
How to handle High Sierra today
If you are still running a machine on the macOS 10.13 High Sierra update, you need to be careful. Apple stopped pushing security updates for it years ago.
Your biggest risk isn't the OS itself, but the browser. Safari 11 is a Swiss cheese of security vulnerabilities by modern standards. If you're on 10.13, you absolutely should be using a third-party browser like Firefox (specifically the Extended Support Release) or specialized projects like OpenCore Legacy Patcher to get a newer OS onto your hardware.
Actionable Next Steps for High Sierra Users
If you have a Mac stuck on 10.13 or are thinking about reviving one, here is what you should actually do:
- Check your drive type. If you are running High Sierra on a mechanical hard drive, replace it with a SATA SSD immediately. APFS is brutal on spinning platters, and a $20 SSD will make the machine feel 5x faster.
- Verify your Security. Go to System Preferences > Security & Privacy. Make sure FileVault is turned on. Even with the old OS, disk encryption is your best defense against physical theft.
- Use a modern browser. Do not use the built-in Safari. Download the latest version of Chrome or Firefox that still supports 10.13 to ensure you have at least some protection against web-based exploits.
- Look into OpenCore. If your hardware is still solid (like a 2012 MacBook Pro), look into the OpenCore Legacy Patcher community. They have made it possible to run macOS Monterey or even Ventura on machines that officially "died" at High Sierra.
- Backup with Time Machine. APFS snapshots made Time Machine much more reliable in High Sierra. If you haven't backed up lately, do it. The "local snapshots" feature in 10.13 means you can often recover a deleted file even if your external backup drive isn't plugged in.
High Sierra wasn't about the mountain peaks; it was about the foundation. It changed how our data is stored, how our graphics are processed, and how our privacy is guarded. It wasn't flashy, but it was necessary.