What is Library Validation?
Library Validation is closely related to SIP. Library Validation is an OS feature introduced by Apple starting from macOS 10.10 and iOS 8 and is a policy governing the loading of dynamic link libraries into the process space of applications. This is a feature that any application can enable while
developing their software.
If an app has library-validation enabled (which is default enabled in new Xcode projects) the app will not accept code injected by MacEnhance apps, even with SIP disabled.
You can disable Library Validation using this command in Terminal.app:sudo defaults write /Library/Preferences/com.apple.security.libraryvalidation.plist DisableLibraryValidation -bool true
To re-enable Library Validation run the same command but replace true with false.
A reboot is required for changes to take effect.