The first step to diagnose is to open Terminal and open them in the terminal via Deluge.app above is a directory and we can navigate to the binary located at Deluge.app/Contents/MacOS/Deluge and execute the actual binary to see a more actionable error Sh 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 $ /usr/local/Caskroom/deluge/1.3.12/Deluge.app/Contents/MacOS/Deluge Traceback ( most recent call last ) : File "/usr/local/Caskroom/deluge/1.3.12/Deluge.app/Contents/MacOS/Deluge-bin" , line 5, in <module> from pkg_resources import load_entry_point File "pkg_resources/__init__.pyc" , line 37, in <module> File "email/parser.pyc" , line 12, in <module> File "email/feedparser.pyc" , line 27, in <module> File "email/message.pyc" , line 16, in <module> File "email/charset.pyc" , line 13, in <module>…