Open Disk Utility (found in Applications > Utilities) and run First Aid on your startup disk to ensure there are no errors before the OS rewrite begins. 3. How to Update: Step-by-Step

Catalina will not run 32-bit apps . Use a tool like Go64 or check About This Mac > System Report > Legacy Software to see which apps will stop working.

On High Sierra 10.13.6, you will often not see the Catalina update in the standard "Software Update" window. You must typically find it in the . Upgrade to macOS Catalina. - Apple

Use the built-in Time Machine tool to create a full system backup to an external drive. This is your safety net if the installation fails.

Upgrading from to macOS Catalina 10.15 is a significant jump. This transition not only modernizes your system but also fundamentally changes how your Mac operates—most notably by ending support for 32-bit applications .

Do not skip these steps, as the upgrade to Catalina changes your drive format to and removes 32-bit app support.

Before starting, ensure your Mac model officially supports Catalina. Because Catalina requires a , some older machines that ran High Sierra cannot move forward to 10.15. Compatible Models: MacBook: 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 Mac Pro: Late 2013 or newer Minimum System Requirements: Memory: At least 4GB of RAM .

Below is a comprehensive guide to help you prepare for and complete this upgrade safely. 1. Check Hardware Compatibility

Approximately 15GB to 18.5GB of available disk space for the installation. 2. Critical Pre-Upgrade Steps