Calibre Companion and OneDrive Business

[datostar]

Microsoft seem to apply a very strict demarcation between business and personal accounts. I recently had occasion to install Outlook on Windows 11 which comes with the Mail app which cannot handle certain email formats. I do have a personal Office 365 account. I downloaded and installed Outlook and on starting it it flagged up the username for a long unused old education account. When I entered my Office 365 username it told me that personal accounts were not valid. I no longer had the password for the old education account so couldn't get any further even after deletion and reinstallation of Outlook. Solution - I discovered a beta version of the new Outlook and downloaded that. It worked fine.