Let’s be honest. Running an older Mac can feel like living in a time capsule. You open your laptop, look at that brushed metal finish, and realize the software is basically a relic of a different era. But here is the thing: some of these older machines are tanks. They refuse to die. If you are sitting there with a mid-2010 MacBook Pro or an old iMac that’s still chugging along on Sierra or El Capitan, you've probably realized that the modern web is starting to break for you. This is exactly why you need to upgrade to macOS High Sierra. It’s the "Goldilocks" zone for vintage hardware—new enough to support the Apple File System (APFS) but old enough to actually run on hardware that modern macOS versions wouldn't touch with a ten-foot pole.
High Sierra, or macOS 10.13, wasn't exactly a visual revolution. It looked almost identical to its predecessor. However, under the hood, it changed how Macs think about storage. It was the transition point. If you don't make this jump, you're stuck with the old HFS+ file system, which is honestly sluggish on modern SSDs. Upgrading is a necessity for security, but mostly, it’s about making sure your computer doesn't become a very expensive paperweight when Safari stops loading your banking site.
Is Your Mac Actually Invited to the Party?
Before you get excited, we need to check the guest list. Apple is pretty ruthless about cutting off older models. Generally speaking, if your Mac was made before late 2009, you’re probably out of luck unless you want to mess around with "patchers," which is a whole different headache we aren't covering today.
Basically, you need a MacBook or iMac from late 2009 or later. If you have a MacBook Air, MacBook Pro, Mac mini, or Mac Pro, you’re looking at a 2010 cutoff date. It is a bit weird—some older plastic MacBooks made the cut while sleeker Pro models didn't. You can check this by clicking the Apple icon in the top left and hitting "About This Mac." If it says 2011 or 2012, you are totally fine. If it says 2008? Well, it might be time to look at Linux or a new machine.
Memory matters too. Apple says 2GB of RAM is enough. Apple is lying. Technically, it will boot. Practically, it will be painful. You want at least 4GB, but honestly, 8GB is the sweet spot for High Sierra. If you’re still running on a spinning hard drive (HDD), this upgrade will feel slow at first because of the file system conversion. If you can, swap that old drive for a cheap SATA SSD before you start. It's the single best thing you can do for an old Mac.
The "Hidden" Link: Finding the Installer
Here is the most annoying part of the whole process. If you open the Mac App Store right now and search for "High Sierra," you might find... nothing. Apple hides old versions of macOS like they’re embarrassing family secrets. They want you on the latest version, but if your hardware can’t run Sonoma or Ventura, the App Store just gives you a blank stare.
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You have to use a direct link. Apple hosts these on their support pages, but they often redirect weirdly. The most reliable way to upgrade to macOS High Sierra is to find the official Apple Support article titled "How to download and install macOS." Within that page, there’s a link that opens the App Store to the "hidden" High Sierra page.
- Open Safari (Don't use Chrome for this, it sometimes fails to trigger the App Store redirect).
- Go to the Apple Support page for legacy macOS downloads.
- Click the link for macOS High Sierra 10.13.
- The App Store should launch automatically.
- Hit "Get" or the cloud icon.
The file is about 5GB. Depending on your Wi-Fi, go grab a coffee. Or a sandwich.
The Backup: Don't Be That Person
I've seen it a hundred times. Someone starts the upgrade, the power flickers, or the old hard drive decides it's had enough, and suddenly a decade of photos vanishes. High Sierra converts your drive to APFS. This is a major structural change to how data is stored. If it fails midway through, your data is essentially in a blender.
Use Time Machine. Plug in an external drive and let it finish a full backup. If you don't have an external drive, move your most important documents to iCloud, Google Drive, or a thumb drive. Just don't skip this. Seriously.
Walking Through the Installation
Once the installer finishes downloading, it will probably pop up automatically. If it doesn't, check your "Applications" folder for an app called "Install macOS High Sierra."
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Double-click it. You’ll see a nice picture of a mountain.
The process is mostly "Click Next and Agree to things you won't read." However, there is one specific moment where it asks which disk you want to install on. Choose your main drive (usually named Macintosh HD). If you are on an SSD, the installer will automatically convert the drive to APFS. You don't get a choice here, and honestly, you don't want one. APFS is way faster for file copying and much more stable.
Your Mac will restart. Probably several times. The screen will go black. A white Apple logo will appear with a progress bar that will lie to you. It might say "10 minutes remaining" for half an hour. This is normal. The computer is moving millions of files around. Don't touch the power button. Just let it do its thing.
Common Roadblocks and How to Smash Them
Sometimes, things go sideways. One common error is the "Installer payload failed signature check." This sounds scary, but it usually just means your Mac’s internal clock is wrong. If the battery on the motherboard (the PRAM battery) is old, the date might have reset to 2001. The installer sees this, thinks the software is from the future, and freaks out.
You can fix this by opening "Terminal" from the Utilities menu in the installer and typing date to see the current time. If it's wrong, you use a specific command to set it to the current date. It's a weird, nerdy fix that solves 90% of installation failures.
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Another issue? Lack of space. High Sierra needs about 15GB to 20GB of free space to perform the "shuffle" during installation. If your drive is red-lined, the installer will quit. Delete those old movie downloads or clear your cache before you start.
Why High Sierra Still Holds Up in 2026
You might wonder why we are even talking about an OS that came out years ago. The reality is that High Sierra was the last version of macOS to support 32-bit apps reliably. If you have an old version of Microsoft Office or some obscure photo editing software that you paid for once and refuse to give up for a subscription, High Sierra is your sanctuary.
It’s also surprisingly snappy. Because it doesn't have all the heavy transparency effects and "Stage Manager" features of modern macOS, it runs quite well on older Intel chips. It makes a 2012 MacBook Air feel usable again. You can browse the web, write papers, and even do some light coding or photo work without the fans sounding like a jet engine taking off.
Security Realities
We have to be realistic. Apple stopped pushing security patches for High Sierra a long time ago. This means that if a major vulnerability is discovered in the core OS, Apple isn't coming to save you.
Does this mean you’re going to get hacked the second you go online? No. But it does mean you should be smarter. Don't use the old version of Safari that comes with the OS; it hasn't been updated in years. Instead, download the latest version of Firefox or a Chromium-based browser that still supports 10.13. These browsers often maintain their own security layers, giving you a much safer window into the internet than the built-in tools.
Actionable Next Steps to Get It Done
Don't just read this and let your Mac continue to rot on an even older OS. Here is exactly what you should do in the next hour to get this sorted:
- Check your model: Click the Apple logo > About This Mac. If you are 2010 or newer, you are almost certainly good to go.
- Clear the deck: Delete 20GB of junk. Empty the trash. It feels good anyway.
- The Safety Net: Run a Time Machine backup. If you haven't done one in months, do it now.
- Grab the "Secret" Link: Use Safari to go to the Apple Support site and trigger the High Sierra download in the App Store.
- Start the Install: Run the installer and walk away. Let it finish the APFS conversion without interruption.
- Post-Install Update: Once you're in, go to the App Store and click "Updates." There are usually "Security Updates" and "Supplemental Updates" that came out after the main installer was built. Install all of them.
- Switch Browsers: Download Firefox. It’s one of the few modern browsers that stayed compatible with older macOS versions longer than most, and it will keep your web experience much more stable.
Upgrading isn't just about getting new features. It's about extending the life of hardware that is perfectly capable of working. A 2012 Mac with an SSD and High Sierra is still a better computer for daily tasks than most $300 laptops you'd buy at a big-box store today. Give your old machine a second life. High Sierra is the way to do it.