Hrm. Version 1.20 shows identical behavior, so I decided to go down a few versions. In version 1.16, it appears to be solved. In that version, BitComet 'appears' to hang and becomes unresponsive during, what Im guessing is the initial creation of the torrent, and also when you start the torrent if it's not started yet (and also if you stop the running torrent). However, that only takes a few seconds, and after that BitComet behaves exactly as expected again. Im not sure if 1.16 is the last version in which things still work (as I really dont wanna try 1.17,1.18,1.19 unless I have to), so Im hoping that this gives enough clues on where to look for the cause of the issue ?