How To Update Macos High Sierra 10.13.6 To 10.15 Updated Jun 2026
: Use Time Machine to back up your Mac before starting.
Your Mac needs at least 4GB of memory and roughly 12.5GB to 18.5GB of available storage space to run the installation smoothly. Step 2: Check for 32-Bit App Compatibility
: Ensure you have a stable broadband connection for the 8 GB download. 3. Download and Install
Double-check your specific model at everymac.com or Apple’s official support page. And remember – you can always download the Catalina installer from the App Store, even if Apple technically says your Mac is “vintage.” how to update macos high sierra 10.13.6 to 10.15
Known Catalina bug during firmware updates. Fix: Be patient – up to 2 hours. If still stuck, force restart by holding power button. Upon reboot, the installer often resumes correctly. If not, boot into Recovery Mode (Cmd+R) and re-run the installer.
This method erases the hard drive, providing a fresh system free of legacy errors. It requires a USB flash drive (16GB minimum).
Once the download finishes, the installer should open automatically. : Use Time Machine to back up your Mac before starting
The macOS Catalina installer is a large file, and the installation process requires significant free space for temporary files. It's recommended to have at least 20GB of free space to ensure a smooth installation. You can free up space by deleting unnecessary files, emptying the Trash, and moving large media libraries to an external drive.
Once the download finishes, the installation program will launch automatically on your desktop, displaying a large macOS Catalina window. Click on the welcome screen. Read and Agree to the software license agreement.
The most significant architectural change in macOS Catalina is the . High Sierra natively supported both 32-bit and 64-bit software, but Catalina runs only 64-bit applications. Older versions of Microsoft Office (like Office 2011), Adobe Creative Cloud apps, and various older games will completely cease to function after this update. How to check for 32-bit apps before upgrading: Click the Apple menu and choose About This Mac . Click the System Report... button. Fix: Be patient – up to 2 hours
Once the progress bar completes, you will be greeted by the macOS Catalina login screen. Enter your password to access your upgraded system. The first login requires a few setup steps:
If you have a Fusion Drive (iMac, some Mac minis), the installer will handle it automatically. Do not attempt to split it.
Give it another 30-60 minutes. If it is frozen for hours, turn it off and try to restart.
Catalina drops support for 32-bit apps. Go to Apple Menu > About This Mac > System Report > Software > Applications . Look for the “64-bit” column. If any critical apps say “No,” they will not run after the update. This includes older versions of Microsoft Office, Adobe CS6, and many games.
Open the Mac App Store and click Updates in the sidebar to download the 64-bit compatible versions of your third-party applications.