Very occasionally, Commander won't load.
This could be caused by a corrupt component or bad installation, in which case a reinstallation may resolve.
However, sometimes it is useful to run Commander from a Terminal Window to see if any errors are issued that are preventing it from loading.
This command, including the quotes, can be used to invoke Commander
"/Library/Application Support/UPDD/UPDD Commander.app/Contents/MacOS/UPDD Commander"