É muito simples:
- Faça o download da versão atual de aqui
- Você obtém o arquivo KeePass2.2x.x.pkg - faça um duplo clique no arquivo para iniciar o Instalador
- Confirme a licença e o destino padrão
- Você está pronto: encontre o aplicativo KeePass na pasta "Aplicativos"!
The problems reported on the KeePass forum have been resolved, we have reworked the installation process, KeePass installation is now done by an installer, which should make the installation easier. We are working on further integration with OS X native Cocoa interface, and bundling it with Mono so that a separate Mono download is no longer needed ...