You might have needed to have manually added WS to the firewall(s) including Little Snitch.

(There is a command in the WS installer to auto-add WS to the OSX firewall, but perhaps something prevented this happening or else, it does not work on all systems.)

So do you mean you port forwarded your router? Whichever port that is, then use that for LPE.

You said WireShare/LPE open fine on your other Mac (iMac?), but does it connect ok? If it's fully connected it should show 5 blue bars bottom left-corner of the program.

Have you tried the connection fix options suggested here http://www.gnutellaforums.com/connec...t-connect.html such as disabling DHT, TLS & Ultrapeer mode.

I remember my LW 4 versions on this computer would only connect with TLS disabled. As soon as I did LW would usually quickly connect as an ultrapeer. Obviously an issue related to my particular system.

(Thanks Birdy for the suggestions.)

As far as a particular program not working on a particular system, that happened to me a few years ago. Neither LW 4.18 or the early LW 5 versions would open on my main OSX. I could only run them on an different startup drive on same computer. I was not the only person who had this issue according to LW beta forum OSX discussions at the time. Then one day I realised the problem had mysteriously vanished (a year or two later.)