Trouble getting started
Having trouble getting High Sierra to install? Here are some solutions to try out
High Sierra usually installs without problems, but there are a few common hiccups. If your hardware and system are compatible but you get an error message such as “macOS High Sierra download has failed” or “installation could not continue,” then it could be that your internet connection or Apple’s server is too busy. Try again later, ideally at a quieter time of day.
It might be worth switching from WiFi to an Ethernet cable, so your connection is as reliable as possible. In the Mac App Store, choose Store > Check for Unfinished Downloads, and you should be able to resume any stalled downloads. If not, choose Store > Sign Out, then sign in again.
If you get an error message saying installation has failed, something is missing or damaged, or just “an error occurred” while verifying or installing, restart your Mac, open your Applications folder, locate the installer app (named “Install macOS High Sierra”), and double-click it to run it again. If you get an error message or it won’t run, trash the installer app, then download a fresh copy and open it.
Verify there’s enough free space. To install High Sierra, the target drive needs at least 14.3GB of space available. Check how much you have by choosing Go > Computer and use Get Info (Cmd+I) or turn on Finder’s status bar (View > Show Status Bar), which appears across the bottom of the app’s windows — if you have more than one drive or partition, make sure you’ve selected your Mac’s startup disk.
If you’re using Sierra, the operating system offers some advice on making space. Choose Apple Menu > About This Mac, click the Storage tab, then Manage. Apple provides advice on using this feature, and on freeing up space, at bit.ly/gain-space.
Bear in mind that even if you can install High Sierra, your Mac might not support all its features — check at bit.ly/high-sierra-spec.
The oldest Macs that run High Sierra came with Snow Leopard, but you need at least Mountain Lion to upgrade; if needed, go via Sierra: bit.ly/get1012.