Note: If your Mac is older than the models listed above (such as a Mid 2010 or 2011 model), High Sierra 10.13.6 is your official end-of-the-line operating system. Upgrading further on those machines requires community-developed third-party workarounds like the OpenCore Legacy Patcher. Step 2: The Critical 32-Bit App Warning How do I update my old Mac computer from 10.13.6 to 10.15?
Upgrading from macOS High Sierra to Catalina can bring a new level of performance, security, and access to newer apps to your Mac. By carefully following the preparation steps in this guide and using the official upgrade path, you can make the transition smoothly and confidently.
Spotlight or Time Machine local snapshots. Fix: Run tmutil listlocalsnapshots / in Terminal, then sudo tmutil deletelocalsnapshots / to purge them. Reboot.
If you notice odd behavior (Wi-Fi dropping, sound glitching):
Updating from is a smart move for security and modern software compatibility—provided you don’t rely on 32-bit apps.
Before downloading any files, you must ensure your specific Mac model officially supports macOS Catalina 10.15. Attempting to force an installation on unsupported hardware can result in system instability or a failure to boot.
How to Update macOS High Sierra 10.13.6 to macOS Catalina 10.15
| Issue | Solution | | :--- | :--- | | | Ensure the date and time are correct in System Preferences > Date & Time . An incorrect date can cause certificate errors. Also, try redownloading the installer. | | Installation gets stuck or is very slow | Restart your Mac and try again. Sometimes simply retrying resolves temporary glitches. If the problem persists, boot into Safe Mode (hold the Shift key during startup) and run the installer from there. | | "Installation requires downloading important content" error | This often indicates your Mac is having trouble communicating with Apple's servers. Ensure you have a stable internet connection and try again later. | | 32-bit apps won't open after upgrade | This is not a bug but a feature of Catalina. If you missed a critical 32-bit app in your pre-upgrade check, you have two options: find a 64-bit alternative or, if absolutely necessary, revert to your Time Machine backup to go back to High Sierra. | | Printer or scanner stops working | Your old drivers may be 32-bit. Visit the manufacturer's website to download and install 64-bit drivers for Catalina. |
| 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. |
Choose whether to enable or skip the new digital wellness tracking feature.
Look at the tab. You will see your Mac model and the year it was released (e.g., MacBook Pro (Retina, 15-inch, Mid 2014) ).
Because macOS Catalina is an older release, you will not find it featured on the main page of the Mac App Store. Instead, you need to access it via a direct link. 1. Download the Installer
Before updating, check if you rely on older software (like older versions of Photoshop, Microsoft Office 2011, or some music production software). If you have 32-bit apps you cannot live without, they will stop working after you update. You can check your apps by going to the Apple Menu > About This Mac > System Report > Applications and looking at the "64-bit" column.
How To Update Macos High Sierra 10.13.6 To 10.15 //top\\ Instant
Note: If your Mac is older than the models listed above (such as a Mid 2010 or 2011 model), High Sierra 10.13.6 is your official end-of-the-line operating system. Upgrading further on those machines requires community-developed third-party workarounds like the OpenCore Legacy Patcher. Step 2: The Critical 32-Bit App Warning How do I update my old Mac computer from 10.13.6 to 10.15?
Upgrading from macOS High Sierra to Catalina can bring a new level of performance, security, and access to newer apps to your Mac. By carefully following the preparation steps in this guide and using the official upgrade path, you can make the transition smoothly and confidently.
Spotlight or Time Machine local snapshots. Fix: Run tmutil listlocalsnapshots / in Terminal, then sudo tmutil deletelocalsnapshots / to purge them. Reboot.
If you notice odd behavior (Wi-Fi dropping, sound glitching): how to update macos high sierra 10.13.6 to 10.15
Updating from is a smart move for security and modern software compatibility—provided you don’t rely on 32-bit apps.
Before downloading any files, you must ensure your specific Mac model officially supports macOS Catalina 10.15. Attempting to force an installation on unsupported hardware can result in system instability or a failure to boot.
How to Update macOS High Sierra 10.13.6 to macOS Catalina 10.15 Note: If your Mac is older than the
| Issue | Solution | | :--- | :--- | | | Ensure the date and time are correct in System Preferences > Date & Time . An incorrect date can cause certificate errors. Also, try redownloading the installer. | | Installation gets stuck or is very slow | Restart your Mac and try again. Sometimes simply retrying resolves temporary glitches. If the problem persists, boot into Safe Mode (hold the Shift key during startup) and run the installer from there. | | "Installation requires downloading important content" error | This often indicates your Mac is having trouble communicating with Apple's servers. Ensure you have a stable internet connection and try again later. | | 32-bit apps won't open after upgrade | This is not a bug but a feature of Catalina. If you missed a critical 32-bit app in your pre-upgrade check, you have two options: find a 64-bit alternative or, if absolutely necessary, revert to your Time Machine backup to go back to High Sierra. | | Printer or scanner stops working | Your old drivers may be 32-bit. Visit the manufacturer's website to download and install 64-bit drivers for Catalina. |
| 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. |
Choose whether to enable or skip the new digital wellness tracking feature. Upgrading from macOS High Sierra to Catalina can
Look at the tab. You will see your Mac model and the year it was released (e.g., MacBook Pro (Retina, 15-inch, Mid 2014) ).
Because macOS Catalina is an older release, you will not find it featured on the main page of the Mac App Store. Instead, you need to access it via a direct link. 1. Download the Installer
Before updating, check if you rely on older software (like older versions of Photoshop, Microsoft Office 2011, or some music production software). If you have 32-bit apps you cannot live without, they will stop working after you update. You can check your apps by going to the Apple Menu > About This Mac > System Report > Applications and looking at the "64-bit" column.