Microsoft has fixed a known issue that caused Microsoft 365 applications and Classic Outlook to crash on Windows Server 2016 or Windows Server 2019 systems.

Microsoft 365 (and Office 365 ... in which a document saved to a network shared folder and set to “Always Open Read-Only” would open in “Editing” mode, and another for the entire Office ...

you can just open an Office file then choose to open it in the Microsoft 365 app when prompted. From there you’ll be guided through a one-time setup experience to install the app and connect ...