macOS High Sierra 10.13.6 — macOS

macOS High Sierra 10.13.6 runs on MacBook models from late 2009 onward, MacBook Pro and iMac from mid 2010, MacBook Air and Mac mini from mid 2010, and Mac Pro from mid 2010. That covers a lot of older office machines still doing daily work.

Upgrade an older iMac to High Sierra

1. Check your Mac – Make sure it’s a supported model listed above. You’ll need at least 2 GB of memory and 14.3 GB free storage.
2. Back up – Run Time Machine or clone the drive before any system change.
3. Get the installer – Download the High Sierra disk image from a trusted source.
4. Open the disk image – Mount it and drag the “Install macOS High Sierra” app into your Applications folder.
5. Run the installer – Launch it from Applications, click Continue, and follow the on-screen steps. The Mac restarts automatically.

After the upgrade, the Mac converts its drive to Apple File System (APFS) – that’s normal. Safari now blocks autoplay audio and can open articles in Reader view automatically. Photos adds Curves and Selective Color tools, and the sidebar stays fixed. Spotlight can show flight info like gate and delays. Mail search includes Top Hits. It’s a solid, no-surprise system update for office Macs that need to stay current without moving to a newer macOS version.

Give your Mac a day or two to settle after the upgrade

After the upgrade, give the Mac a day or two to settle. APFS conversion happens during the first restart and the system indexes files in the background. Let it finish before you start any heavy work. Open Photos once and let it rebuild its library — the new sidebar with albums and sorting tools won’t show properly until it finishes scanning. Check that your shared network printers and office drives connect without issues; if they don’t, a quick re-add in System Preferences usually does it.

Test the apps your office relies on. Open Safari and browse a few pages that used to play sound automatically — you’ll notice they stay quiet now. That autoplay block is a small thing, but it saves frustration in a shared workspace. If you use Mail with a Gmail account, move a test message between folders to confirm the fix for that issue is working.

AirPlay 2 multi-room audio arrives in the 10.13.6 update

The jump to build 17G66 is mostly about polish and reliability. The headline addition is AirPlay 2 multi-room audio support for iTunes. If your office has multiple AirPlay speakers or a few Macs around the building, you can play music through several rooms at once from one library. It works with iTunes as it always has — no extra setup beyond choosing the speakers.

The update also fixes two specific problems. Photos now recognizes AVCHD media from some cameras that it previously ignored, which matters if anyone imports video from a camcorder. And Mail users who move messages from a Gmail account to another account should no longer see the message disappear from the source folder. The rest is the usual stability and security improvements — fewer surprises, fewer patches needed later.

Skipping the backup before the upgrade is the most common slip

The most common slip I see in our office is skipping the backup before the upgrade. The installer warns you, but people assume their files are fine. APFS conversion is reliable, but any major system change carries risk. Take the twenty minutes to run Time Machine.

Another mistake is treating the APFS conversion as optional. The installer doesn’t offer a choice — it converts the boot drive. That’s fine, but some users panic when they see the disk utility showing a new filesystem name. APFS is faster and includes built-in encryption, so it’s a net gain. Leave it be.

Beginners also overlook the new Photos editing tools. Curves and Selective Color aren’t hidden in a submenu — they’re right in the toolbar, but people who never clicked around in previous versions miss them. Open a photo and look for the adjustment panel. It’s worth knowing they’re there, especially if you handle product shots or scanned documents.

Real scenario: an office manager setting up a shared iMac

An office manager at a small real estate agency has an iMac from late 2009 that serves as the shared booking and photo station. Agents use it to check email, browse listings, and light-edit property photos. The old macOS started showing security warnings, so the manager upgrades to High Sierra 10.13.6.

After the install, the first task is getting the printer queue working again — the old driver needed a reinstall, but the HP utility still supports macOS 10.13. The manager opens Photos, imports a folder of listing shots, and uses the new Selective Color tool to fix a white balance issue on a kitchen photo without launching a separate app. Safari’s Reader mode makes the MLS site easier to scan on the 24-inch screen. And when agents play a walkthrough video from a camera, Photos picks it up right away thanks to the AVCHD fix.

The AirPlay 2 update doesn’t change much for this office, but the multi-room audio feature means someone can stream music from iTunes to a speaker in the back room while the front desk stays quiet. It’s a small upgrade that makes the shared workspace a little less noisy. For a machine that was already doing the job, High Sierra keeps it useful without forcing new hardware.

• Adds AirPlay 2 multi-room audio support for iTunes.
• Improves stability and security.
• Fixes a Photos issue with AVCHD media from some cameras.
• Fixes a Mail issue moving Gmail messages to another account.

• macOS 10.13.5
• Intel architecture
• 2 GB of memory
• 14.3 GB of available storage