Many thanks! Frankly I only work with Outlook Calendar (Microsoft 365, Outlook Exchange) and Calengoo. So, I need to sync my Outlook Calendar with Google Calendar, then go into Google Calendar (desktop), then go into Chrome Google Calendar, then launch Google Drive (I use OneDrive), then try to safe file on Google Drive, then... then ..
Frankly, I don't know.
Anyway, right now it seems there are sync issues with Outlook servers: -all- Calengoo entries are gone. Calengoo is totally empty... Hopefully, one day, this will be fixed.