Good evening,
The Merkuro calendar freezes at launch for me too. This is a first installation. My system is KDE Neon user edition. Contacts opens and seems to work, but Merkuro Calendar won’t open. I’ve filed a bug report.
Thanks for your answers.
P-S: I did see the two old threads about this. But I haven’t managed to activate an answer there???
Does it work if you copy LANGUAGE=C merkuro-calendar into konsole and hit enter?`