How To Update Macos High Sierra 10136 To 1015 Better Jun 2026

Select your main drive (usually "Macintosh HD") as the destination. Enter your when prompted.

Although you're already running High Sierra, not all models that run High Sierra are officially compatible with Catalina. Check your model against the list below.

Upgrading from macOS High Sierra 10.13.6 to Catalina 10.15 is a rewarding project that brings a wealth of new features, security, and app compatibility to your Mac. While it requires careful preparation, following this guide—from verifying compatibility and backing up your data to executing the upgrade and troubleshooting—will help ensure your transition is successful and your data remains safe. Good luck with your upgrade! how to update macos high sierra 10136 to 1015

This error happens when the digital security certificate of an older installer has expired. To fix this, delete the installer from your Applications folder, clear your Mac App Store cache, and redownload the file to obtain a fresh copy with updated certificates. Stuck on the Apple Logo

Rollback options

Apple no longer prominently features Catalina on the App Store because newer OS versions exist. Here’s how to find it.

Turn on Time Machine or select from the Time Machine menu bar icon. Step 5: Download and Install macOS Catalina Select your main drive (usually "Macintosh HD") as

Upon booting into Catalina, you will notice major changes:

Force restart (hold power button). The installer might resume correctly. If not, restore from Time Machine backup and try again after running Disk Utility. Check your model against the list below