Fix: Boot into Safe Mode (hold Shift at startup) and clear caches and Time Machine local snapshots:
Updating from High Sierra to Catalina is a straightforward process via the Mac App Store, provided you have verified hardware compatibility and backed up your data. However, the loss of 32-bit app support makes this a "point of no return" for users reliant on older software.
This is the most significant hurdle when upgrading from High Sierra to Catalina. macOS Catalina completely drops support for 32-bit applications. High Sierra can still run both 32-bit and 64-bit apps. To check which of your apps will break: how to update macos high sierra 10136 to 1015
Older versions of Microsoft Office (pre-2016), Adobe Creative Suite (CS6 and earlier), and many legacy games will cease to function. You must either find 64-bit alternatives, update to newer versions, or accept that these programs will be lost.
Not every Mac that runs High Sierra can run Catalina. Before you proceed, verify your Mac model. Fix: Boot into Safe Mode (hold Shift at
Compatible Macs for macOS Catalina (10.15):
To find your Mac model: Click the Apple logo → About This Mac. Under “Overview,” you will see the model and year. Updating from High Sierra to Catalina is a
If your Mac is older than 2012, you cannot install Catalina or newer versions natively. In that case, consider staying on High Sierra or using a patching tool (not recommended for security).
You need at least 12.5 GB to 20 GB of free storage space for the download and installation process.