So.. tried to use this migration option.. (yes, it was synced)

restarted the client and now I get this: (pc restart doesn't help)

What version is that? An earlier version (maybe... 0.4.6 and earlier?) had a bug in the UI where sometimes the config file would get set to 'undefined'. You can usually fix it by deleting 'config.json'. This bug has been fixed in the most recent version, 0.4.8