: If you already have Sierra 10.12 and just need to patch it to the latest version, Apple provides the 10.12.6 Combo Update (2.15 GB) on their Support site . System Requirements
If the App Store link fails, open (Applications > Utilities) and run: Download Mac Os Sierra 10.12 Dmg
You can download the macOS Sierra 10.12 DMG installer directly through official Apple support pages : If you already have Sierra 10
Always verify your DMG via checksums, set the system date correctly if the certificate fails, and consider creating a bootable USB for future use. Preserve that DMG on an external drive or cloud storage; as time passes, clean copies of macOS Sierra become more valuable for retro-computing. A downloaded macOS Sierra DMG serves multiple distinct
A downloaded macOS Sierra DMG serves multiple distinct operational workflows. A. Creating External Bootable Media
If you're having trouble finding the download link, you can try visiting the Apple Support website: