It's 2026. macOS High Sierra is, by all tech standards, ancient history. Yet, every single day, thousands of people are out there scouring the web to download High Sierra DMG files. Why? Because sometimes the "latest and greatest" isn't what you need. Maybe you’re reviving a 2010 MacBook Pro that can’t handle anything newer. Maybe you have legacy software that refuses to run on APFS or the newer 64-bit-only architectures of modern macOS. Or maybe you're just a tinkerer building a specific virtual machine environment for testing.
Whatever the reason, finding a clean, bootable image of macOS 10.13 is surprisingly annoying. Apple makes it harder than it should be to look backward. If you try to find it in the App Store on a M3 or M4 Mac, it simply won't show up. It’s like Apple wants to pretend the year 2017 never happened.
The Problem With Most High Sierra Downloads
Let's be real. If you Google "download High Sierra DMG," you're going to find a lot of sketchy sites. You know the ones. They’re covered in "Download Now" buttons that are actually ads for malware or some weird browser extension. Honestly, it’s a minefield.
The biggest risk isn't just a virus. It’s a corrupted installer. If the DMG file wasn’t created correctly from the original BaseSystem.dmg, your installation will likely fail halfway through, or worse, leave you with a non-bootable drive. Most people don't realize that Apple's digital certificates expire. A DMG created five years ago might have an expired certificate that triggers a "This copy of the Install macOS High Sierra application is damaged" error. It’s not actually damaged; it’s just that the security certificate is out of date.
You’ve got to be careful.
How to Get an Official High Sierra DMG (The Right Way)
The safest way is still through Apple, even if they hide the link. You can't just search the App Store. You need the direct link. Apple maintains a support page specifically for downloading older versions of macOS.
When you click that link, it opens the Mac App Store to a hidden page. But here is the catch: your current Mac must be compatible with High Sierra to even download the installer. If you're on a brand-new iMac, the App Store will literally tell you that the software is "not compatible with this computer." It’s frustrating.
💡 You might also like: Why Your 3-in-1 Wireless Charging Station Probably Isn't Reaching Its Full Potential
Using the "softwareupdate" Command in Terminal
If the App Store is being difficult, there is a "pro" way. Open your Terminal. You can actually use the command line to fetch installers directly from Apple's servers.
Input this: softwareupdate --fetch-full-installer --full-installer-version 10.13.6
This bypasses the GUI of the App Store. However, even this method has limitations. It usually only works on Intel-based Macs. If you're on Silicon, you're basically out of luck using this specific tool for an OS this old.
Why People Still Choose High Sierra in 2026
High Sierra was a bridge. It was the last version of macOS to support 32-bit apps fully without constant nagging or performance drops. For professionals in the music industry or specialized engineering, this is vital.
Think about old Pro Tools plugins. Some of that stuff costs thousands of dollars and the developers went bust a decade ago. If those plugins don't work on Big Sur or Monterey, you're stuck. High Sierra is the "forever home" for that hardware.
Also, it was the introduction of APFS (Apple File System). While APFS is great for SSDs, High Sierra was unique because it could still run on HFS+ for spinning hard drives. If you're reviving an old Mac Mini with a mechanical drive, High Sierra is often the sweet spot between "modern enough to browse the web" and "not so heavy it kills the hardware."
📖 Related: Frontier Mail Powered by Yahoo: Why Your Login Just Changed
Converting an Installer to a DMG
Usually, when you download the installer from Apple, it comes as an .app file in your Applications folder titled "Install macOS High Sierra." This is not a DMG.
To turn this into a download High Sierra DMG that you can use for a virtual machine like VMware or VirtualBox, or to burn to a USB, you have to use a script. You basically create a blank disk image, mount it, and use the createinstallmedia tool inside the app package to "burn" the installer onto that image.
It’s a bit of a process. You’ll need at least 12GB of space.
Dealing with the "Damaged Installer" Error
If you finally get your hands on a DMG and try to install it, you might hit a wall. The installer says it’s "damaged." Don't delete it yet!
This is almost always a date issue. The certificates in the High Sierra installer expired years ago. The fix is weirdly simple:
- Disconnect your Mac from the internet (turn off Wi-Fi).
- Open Terminal from the Installer Utilities menu.
- Type
date 0101010118and hit enter.
This sets your system clock back to January 1st, 2018. Suddenly, the certificate is "valid" again, and the installer will run perfectly. Just remember to fix the date once the installation is finished so your web browser doesn't freak out.
Is it safe to download DMGs from third-party sites?
Look, I'll be honest. Sometimes you literally cannot get it from Apple because you don't have a compatible Mac to run the download. In those cases, people turn to sites like the Internet Archive (archive.org).
👉 See also: Why Did Google Call My S25 Ultra an S22? The Real Reason Your New Phone Looks Old Online
The Internet Archive is generally safer than "CrackedMacApps.com" or whatever, because you can often find uploads from reputable archivists. However, you should always verify the SHA-256 checksum of the file if you can find the original hash online. If the hash doesn't match, someone has messed with the code. That’s a huge red flag.
Actionable Steps for a Successful Install
If you are ready to move forward, don't just wing it. Follow a clean path.
First, identify exactly why you need the DMG. If it's for a bootable USB, ensure you have a drive that is at least 16GB. Small 8GB drives often fall just short because of how the disk headers are calculated.
Second, if you're using a modern Mac to create this installer for an old Mac, use a tool like "Mist" (a great open-source utility on GitHub). Mist can often download these older installers directly and even wrap them into a DMG or ISO for you without you having to mess around with Terminal commands. It saves a ton of time and avoids the "incompatible computer" error in the App Store.
Third, once you have your download High Sierra DMG, test it in a Virtual Machine before you wipe a real computer. It takes ten minutes to see if it boots. If it does, you're golden.
Finally, always remember the "Date Trick" mentioned above. It is the number one reason people fail to install High Sierra. Set that clock back to 2018, keep the internet off during the initial phase, and your vintage hardware will be back up and running in no time.
High Sierra might be old, but for the right hardware, it’s still one of the most stable versions of macOS ever released. Happy installing.
Next Steps for a Clean Installation:
- Verify your hardware: Ensure your Mac is from 2009 or later (Late 2009 iMac/MacBook or newer).
- Clear the Certificate Hurdle: Use the Terminal command
date 0101010118if you encounter "damaged" file errors. - Format Correctly: Use macOS Journaled (HFS+) for older mechanical drives or APFS for SSDs to ensure the best performance once the DMG is deployed.