There are multiple reasons why Ferdi could refuse to start. Please try the following steps in the right order and try starting Ferdi again after each step.
- Open the Task Manager (Windows) or Activity Monitor (Mac) and stop all "Ferdi" process if there are any
- Delete the Ferdi .exe (Windows) or .app (Mac) and redownload it from https://getferdi.com. This will probably log you out of your account but won't delete any of your data.
- Open "%appdata%/Ferdi" (Windows), "~/Library/Application Support/Ferdi" (Mac) or "~/.config/Ferdi" (Linux) in your File Explorer or Finder and delete the "config/settings.json" and "config/proxy.json" files.