Simple import of multiple PST files for a single user
This community script imports multiple PST files into a user mailbox or archive.
Offboarding primary mailbox fails
When you use the Exchange Online Portal to move a primary cloud mailbox to on-premise while keeping the archive mailbox in Office 365 the request fails.
Move Cloud Archive Enabled Primary Mailbox to Office 365
When use the Office 365 Portal to move an on-premise mailbox to Office 365 (aka Office 365 Onboarding) you cannot select to move only the primary mailbox.