As of early 2025, Apple has discontinued Mac App Store support for macOS High Sierra. Users on High Sierra (10.13) report missing interface elements and failed sign-in attempts when trying to access the store. This means you cannot simply open the App Store and search for Catalina directly.
Wait for the backup to finish completely before moving forward. Step 4: Download and Install macOS Catalina
If you notice odd behavior (Wi-Fi dropping, sound glitching):
If you have a Fusion Drive (iMac, some Mac minis), the installer will handle it automatically. Do not attempt to split it. how to update macos high sierra 10.13.6 to 10.15
Click and follow the on-screen instructions to complete the installation.
Once your desktop loads, go to Apple Menu > System Preferences > Software Update to catch up on any minor security patches released for Catalina (bringing you to the final version, 10.15.7).
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 As of early 2025, Apple has discontinued Mac
For persistent, unexplained errors, you have two advanced options:
Skipping preparation is the #1 cause of failed updates. Take these steps seriously.
Apple restricted macOS Catalina to specific hardware configurations. To check your model, click the (\Apple) in the top-left corner of your screen and select About This Mac . Wait for the backup to finish completely before
To update your Mac from macOS High Sierra 10.13.6 macOS Catalina 10.15
You cannot simply “Check for Updates” from System Preferences on High Sierra. Apple’s Software Update will only offer you macOS Mojave (10.14) first, then maybe Catalina. Instead, use the direct method.
macOS Catalina dropped support for many older Mac models because it requires graphics hardware that supports Apple's Metal technology. Before downloading anything, verify that your Mac is on the official compatibility list.