What to do when Ichthyop suddenly fails to launch ?

Situation: without apparent reason, Ichthyop fails to launch, either from GUI or command line. It looks like it starts and crashed instantly.

Solution: delete Ichthyop persistence files (the files that store the information to restart your ichthyop session as it was when you last closed it) In Windows environment such files are gathered in a hidden directory ~/AppData/Local. In this folder delete the ichthyop directory of the previmer/ichthyop directory. In Linux or Mac environement delete the ~/.ichthyop folder. Try to run Ichthyop again.