BackToCatalina Beta

Restores macOS Catalina UI on newer versions of macOS. Works on both Apple silicon and Intel running macOS Tahoe, macOS Sequoia, macOS Sonoma, and macOS Ventura. Support for macOS Tahoe is heavily experimental. Featured on MacGeneration and MacTechNews. Contributions are welcome!

Installing BackToCatalina Beta

Disable System Integrity Protection by running csrutil disable in macOS Recovery
Install ammonia
Install BackToCatalina.pkg and reboot

Installing BackToCatalina Beta on macOS Tahoe causes Dock, Control Center, and Notification Center to appear without any background material. To fix this, install launchbad-revived.

To get full-width sidebar selection highlight, open Terminal and run:

defaults write -g NSSidebarUsesGoldenMetrics -bool false

If an app has compatility issue with BackToCatalina, add the executable name to the end of /private/var/ammonia/core/tweaks/libBackToCatalina.dylib.blacklist

Uninstalling BackToCatalina Beta

In Terminal, run the following and reboot:

launchctl unsetenv FEATUREFLAGS_DISABLED
defaults delete -g NSSidebarUsesGoldenMetrics
sudo rm -rf /private/var/ammonia/core/tweaks/libBackToCatalina*
sudo defaults delete /Library/Preferences/FeatureFlags/Domain/SwiftUI.plist

Contributing to BackToCatalina Beta

If you're a developer, it's easy to make contributions. To get started, clone this repo and build BackToCatalina in Xcode. This automatically generates an updated BackToCatalina.pkg installer at the project directory which you can install and test. To build a universal installer for Apple silicon and Intel, change the destination from "My Mac" to "Any Mac".

To iterate changes and fixes more quickly, choose Product > Schemes > Edit Scheme > Run, and change the Build Configuration from Release to Debug. Then open Terminal and run:

sudo chmod -R a+rwx /private/var/ammonia/core/tweaks

After this, building BackToCatalina in Xcode automatically updates the installed libBackToCatalina.dylib. When using the Debug build configuration, other assets such as libBackToCatalina.dylib.blacklist and SystemAppearance.bundle must be updated manually.