Due to security restrictions on Java - specifically on macOS - there is occasionally a need to permit the Blackbird editor to launch.

Go to your system preferences

Access security and privacy pane

If the last app attempted to open was the Blackbird launcher then it should be listed on this list

Select "Open anyway" - this should then launch.

Note: if you do not have permissions to access this menu or do not have this option, please contact your system administrator

See more here: https://support.apple.com/en-gb/guide/mac-help/mh40616/mac