Make a list of these apps. You will need to either find an updated 64-bit version, locate an alternative app, or be prepared to live without them.
30 GB minimum.
Check the box for or click the Time Machine icon in the menu bar and select Back Up Now . Wait for the backup process to complete fully. Step 4: Download and Install macOS Catalina
Before starting, ensure your Mac model is officially supported. Catalina only runs on Macs with Metal-capable graphics processors: : Early 2015 or newer MacBook Air/Pro : Mid 2012 or newer Mac mini/iMac : Late 2012 or newer : 2017 or newer : Late 2013 or newer Apple Support Note on 32-bit Apps : Catalina is the first macOS to drop all support for 32-bit applications how to update macos high sierra 10.13.6 to 10.15
| Issue | Possible Solution | |--------|--------------------| | “This copy of the Install macOS Catalina application is damaged” | Set date back manually via terminal: date 010100002020 (then rerun installer). | | Insufficient disk space error | Free up space by deleting caches, old iOS backups, large unused apps. | | Installer hangs at “less than a minute remaining” | Wait up to 1 hour; if still stuck, restart and re-run installer from Recovery Mode. | | 32-bit app won’t open | App must be replaced with a 64-bit version or abandoned. No workaround exists. |
Below is a detailed, safe walkthrough to get you from 10.13.6 to 10.15.
Your Mac must be one of the following models to officially run macOS Catalina: : Early 2015 or newer MacBook Air : Mid 2012 or newer MacBook Pro : Mid 2012 or newer Mac mini : Late 2012 or newer iMac : Late 2012 or newer iMac Pro : 2017 or newer Mac Pro : Late 2013 or newer 2. Prepare for the Update Make a list of these apps
Beyond hardware, you also need to check your system resources. Your Mac must be running (which it is, as you're on High Sierra), have at least 4GB of RAM , and possess at least 12.5GB of available storage space . For the safest installation, it's recommended to have 15GB to 20GB of free space to accommodate the download, installation, and post-update file management.
Typically 45–90 minutes depending on drive speed (HDD vs. SSD).
The most critical change introduced in macOS Catalina is the . Catalina exclusively runs 64-bit software. If you rely on older legacy software (such as Microsoft Office 2011, older Adobe Creative Suite apps, or legacy games), those programs will stop working immediately after the upgrade. How to Find Your 32-Bit Apps on High Sierra Click the Apple icon and choose About This Mac . Click the System Report... button. Check the box for or click the Time
How to Update macOS High Sierra 10.13.6 to 10.15 (macOS Catalina)
Apple menu → System Preferences → Software Update → install any available updates (final version is 10.15.7 with security updates through mid-2022).
Your Mac is now fully updated to macOS Catalina 10.15. You can verify this by going back to to check the version number. Open the App Store and click the Updates tab to install any remaining security patches or supplemental updates released for Catalina.
The installation process may take some time, depending on your Mac's specifications and the speed of your internet connection. Here's what you can expect:
When you open an old 32-bit app, Catalina will show: “The application X needs to be updated.” There is no workaround. You must find a 64-bit replacement or keep High Sierra in a separate partition.