Hello @christiaan​,
Welcome to the community!
The app for mac was deprecated recently and will no longer be available. From now on we will have only the extension for Safari which you can find in the App Store as LastPass for Safari. You can find more here: https://support.lastpass.com/s/document-item?language=en_US&bundleId=lastpass&topicId=LastPass/Use_the_LastPass_Mac_App_install_log_in.html&_LANG=enus
Kind Regards,
Alejandrfa
LastPass Tech Support
