How To Update Macos High Sierra 10.13.6 To 10.15 May 2026
Report: Updating macOS High Sierra 10.13.6 to macOS Catalina 10.15
Date: October 2023 (updated for historical context)
Prepared For: Users running macOS High Sierra 10.13.6
Subject: Feasibility, prerequisites, and step-by-step procedure for upgrading to macOS 10.15 (Catalina)
A. Back Up Everything (Time Machine + Optional Clone)
- Time Machine: Connect an external drive (at least double your Mac’s storage). Go to System Preferences > Time Machine > Select Backup Disk > On. Let it complete a full backup.
- Bonus (Optional but recommended): Create a bootable clone using SuperDuper! or Carbon Copy Cloner. This allows you to revert instantly if Catalina has issues.
C. Update High Sierra Completely
Ensure you have all 10.13.6 supplementary updates: how to update macos high sierra 10.13.6 to 10.15
If you want, I can:
Total time: Typically 45–90 minutes depending on drive speed (HDD vs. SSD). Report: Updating macOS High Sierra 10
- Open Safari (or Chrome/Firefox) on your High Sierra machine.
- Go to the official Apple Support page:
https://support.apple.com/macos/catalina
6) Download macOS Catalina installer
- Catalina installer is available from Apple. Open the App Store and search for “macOS Catalina” (or use Apple’s support download link).
- Click Get / Download. The “Install macOS Catalina” app will appear in Applications when download finishes.
- If you have internet issues or App Store won’t download, use a wired Ethernet connection and retry.
Step 5: Let It Restart… a Lot
Your Mac will restart, show a black screen with an Apple logo and progress bar, then restart again. This is normal. Time Machine: Connect an external drive (at least
3) Free up disk space
- Catalina requires ~20–30 GB free to install comfortably. Target ≥30 GB.
- Remove large unused files: