To update macOS High Sierra 10.13.6 to macOS 10.15 Catalina, you must first ensure your hardware is compatible and your data is safely backed up. Catalina is a major transition as it discontinues support for 32-bit applications. 1. Check Hardware Compatibility
~/Library/Application Support/MobileSync/Backup/.date 010101002022 (sets date to Jan 1 2022). Then restart and retry installer.Once you have verified compatibility and backed up your data, follow these steps: how to update macos high sierra 10136 to 1015
Thirty minutes remaining.